JP2018531397A - Optical sensor, system, and method of using the same - Google Patents

Abstract

  Optical sensors, systems, and methods of use thereof are provided. An aspect of the subject system is to direct a first optical signal to interact with the sensing surface at a first angle of incidence and to interact with the sensing surface at a second angle of incidence. A sensor having a configuration for guiding an optical signal. The subject sensors, systems, and methods find use, for example, in the diagnosis of dry eye disease.

Description

Cross-reference of related applications
[0001] This application claims the benefit of priority on the filing date of US Provisional Patent Application No. 62 / 232,320, filed September 24, 2015, the disclosure of which is incorporated herein by reference in its entirety Is incorporated herein by reference. This application also claims the priority date benefit of US Provisional Patent Application No. 62/254099, filed on November 11, 2015, the disclosure of which is hereby incorporated by reference in its entirety. Incorporated in the description.

  [0002] The present invention relates to optical sensors, systems, and methods of use thereof, for example, in the diagnosis of dry eye disease.

  [0003] Dry eye disease, or dry keratoconjunctivitis (KCS), is one of the most frequently established diagnoses in ophthalmology. Current expectations assume that about 40-60 million people in the United States will develop dry eye symptoms. The lack of accurate statistical data regarding the occurrence of dry eye is mainly due to the lack of the best diagnostic equipment. However, since symptomatic patients are not always easily identified, a more troublesome trend is to completely avoid dry eye misdiagnosis or early detection.

  [0004] Pursuing more effective diagnostics will strengthen the ophthalmic practice paradigm, a fact recognized by the pharmaceutical industry. The first ethical drugs for treating dry eye are now on the market, more are on the way, and the methods for diagnosing and monitoring the treatment remain problematic.

  [0005] There is no "gold standard" test that diagnoses dry eye and simultaneously monitors the effectiveness of treatment attempts. One common method is a matrix of subjective observations of symptoms and objective tests (such as Schirmer test, staining technique, tear film destruction time), both of which detect dry eye and its severity It is not unique to the measurement. Considering recent advances in medicines aimed at treating dry eye, timely and parallel advances in diagnostic techniques are required.

  [0006] Tear osmotic pressure, and the degree of solids dissolved therein, is widely accepted by experts in the field as an indicator of the presence and severity of dry eye. The instrument most commonly associated with tear osmometry is the osmometer, but technical limitations have limited the use of the tear osmometer primarily to the research environment.

  [0007] An osmometer is a device that measures the concentration of dissolved solutes in a liquid such as water. Osmometers are widely used in other fields, but osmometers are used in medicine to determine osmolar gaps and trauma cases, especially in toxicology, to monitor mannitol therapy infusions, and surgical procedures Used in applications such as monitoring absorption in glycine uptake by irrigation fluids.

  [0008] Despite the suitability of this technique for measuring tear osmotic pressure, current devices present certain limitations that prevent their widespread use in clinical environments. The most common problem is related to sample size.

  [0009] Almost all commercially available osmometers are designed (and probably technically limited) to measure milliliter sized samples. Tear samples extracted from patients tend to be nanoliter volumes and tend to further complicate the problem, and dry eye patients generally have fewer tears and make sample handling even more difficult To do. Osmometers designed to measure nanoliter sample sizes are not commercially available and are too cumbersome for practical use in a clinical environment. As a result, practitioner ophthalmologists are entrusted with dangerous methodologies and insufficient tools to accurately detect this general condition.

  [0010] Dry eye disease is a complex group of diseases characterized by a reduction in the production of one or more of the three components of the tear film, namely the lipid layer, the aqueous layer, and the mucin layer. A deficiency in one of the tear film components may lead to a loss of tear film stability. Normal vision depends on the surface of the wet eye and requires preconditions of sufficient quality tears, normal composition of the tear film, regular blinks, and normal eyelid closure. If left untreated, dry eye syndrome can cause progressive lesions in the conjunctiva and corneal epithelium, discomfort, corneal ulcers, and ultimately even blindness.

  [0011] The standard treatment is tear replacement therapy, which attempts to mimic the human tear film or to present a more advanced hypotonic version of the tear film. Unfortunately, this general therapy is less effective because dry eye syndrome progresses beyond a mild stage. Furthermore, these treatments do not address the pathogenesis of dry eye.

  [0012] The exact mechanism that causes dry eye is currently unknown and has been the subject of debate for many years. Recently, several different mechanisms have been proposed as possible etiology of dry eye, but in general ideology, dry eye is usually caused by problems with the quality of the tear film that lubricates the surface of the eye It is. More recent studies have shown that dry eye may be the result of hormonal state decline due to aging (more pronounced in postmenopausal women) or an immune-based acquired inflammatory state of the ocular surface Suggests that you may have Other causes of dry eye symptoms include certain drugs (eg, antihistamines, beta blockers), association with certain systemic inflammatory diseases (eg, rheumatoid arthritis), mechanical causes (eg, incomplete Closure), infectious causes (eg, viral infections), and certain neurological causes (eg, LASIK treatment). Despite recent increases in knowledge of the possible etiology of dry eye, appropriate diagnostic criteria, specific objectives of objective diagnostic tests, the role of subjective symptoms in diagnosis, and interpretation of results There is a lack of agreement.

  [0013] Symptoms of dry eye vary greatly from individual to individual. Most patients complain of a foreign body sensation, burning sensation, and general eye discomfort. Discomfort is typically described as itching, dryness, pain, roughness, itching, or a burning sensation. Since the cornea is rich in sensory nerve fibers, discomfort is a feature of dry eye.

  [0014] Despite its high prevalence, dry eye is not always easy to diagnose. The majority of patients have mild to moderate severity symptoms. Although these patients are truly suffering from discomfort, objective signs of dry eye may be overlooked, and without proper diagnosis, the patient can be treated and treated justified by this condition. You may not receive it. The signs and symptoms of dry eye may be misinterpreted as evidence of other conditions such as infectious, allergic, or irritating conjunctivitis. Considering these complications in the diagnosis, the dry eye diagnosis rate is estimated to be about 20%.

  [0015] Diagnosis of dry eye typically begins with a laboratory test. A Schirmer test is typically performed, in which a standardized strip of filter paper is placed at the junction between the middle of the lower eyelid and the lateral third. If less than 5 millimeters is wet after 5 minutes, there is a reason to believe that there is a lack of aqueous tears. The test is quick, inexpensive, and the results are readily available, but it only provides a rough estimate and is not reliable in moderate dry eyes.

  [0016] Dye staining is another method of diagnosing dry eye using either fluorescein or rose bengal, and trained physicians can look for patterns that show dryness under slit lamp observation. Another test, tear division time, is a measure of tear film stability. Normal tear film begins to divide after about 10 seconds, and this time decreases in dry eye patients.

  [0017] An osmometer commonly used in measuring tear osmotic pressure is the Clifton Direct Reading Nanoliter Osmometer developed in the 1960s (Clifton Technical Physics, Hartford, NY). Although not necessarily originally intended for use in measuring tears, it is one of the few instruments that can measure the nanoliter volume of a solution and has found a way to ophthalmology.

  [0018] Clifton osmometers have been produced in limited quantities over the years and are not routinely used outside the laboratory. It is based on a well-known measurement technique called freezing point depression. The Clifton osmometer measures the osmotic pressure of a sample by measuring the freezing point depression. In freezing point depression measurements, water (usually frozen at 0 ° C.) experiences a decrease in its freezing point in the presence of dissolved solutes, the mathematical relationship of which is defined by Raoul's law.

  [0019] The test may be accurate, but requires a highly skilled operator to make the measurement. The test monitors the drop in freezing point temperature by examining the partial volume of the teardrop under a microscope. Because of its limitations and lack of availability, it seems that only a few units remain in the field. Furthermore, each measurement can take more than 15 minutes, coupled with a small sample volume, making the use of the Clifton osmometer a very tedious and inconvenient process. Even though the unit is available, the amount of time required and the operational skills required are not acceptable to a busy clinic or clinic.

  [0020] There is a need for simple and accurate sensors and systems that can diagnose and monitor therapeutic efforts for dry eye disease.

  [0021] Optical sensors, systems, and methods of use thereof are provided. An aspect of the subject system is to direct a first optical signal to interact with the sensing surface at a first angle of incidence and to interact with the sensing surface at a second angle of incidence. A sensor having a configuration for guiding an optical signal. The subject sensors, systems, and methods find use, for example, in the diagnosis of dry eye disease.

  [0022] Aspects of the invention include a sensor comprising a sensing surface, wherein the sensor directs a first optical signal to interact with the sensing surface at a first angle of incidence and the sensing surface at a second angle of incidence. Configured to direct the second optical signal to interact with the. In some embodiments, the sensor comprises a plurality of facets. In some embodiments, the sensor has a frustoconical concave shape. In some embodiments, the sensor comprises a plurality of facets on the inner surface and a plurality of facets on the outer surface. In some embodiments, the sensor comprises two facets on the inner surface and four facets on the outer surface. In some embodiments, the sensing surface is located in the center of the sensor. In some embodiments, the sensing surface comprises a covered area and an uncovered area. In some embodiments, the coated region comprises a translucent film comprising a noble metal. In some embodiments, the noble metal is gold, silver, aluminum, platinum, or palladium. In some embodiments, the translucent film has a thickness in the range of about 0.5 nm to about 200 nm. In some embodiments, the translucent film has a thickness of about 45 nm to about 50 nm. In some embodiments, the covered region comprises an adhesive layer disposed between the sensor and the translucent film. In some embodiments, the adhesion layer has a thickness in the range of about 0.5 nm to about 200 nm. In some embodiments, the adhesion layer has a thickness in the range of about 45 nm to about 50 nm. In some embodiments, the adhesion layer comprises a material selected from chromium, titanium dioxide, titanium monoxide, silicon dioxide, and silicon monoxide. In some embodiments, the adhesive layer has a refractive index that is different from the refractive index of the sensor. In some embodiments, the first angle of incidence ranges from about 40 degrees to about 70 degrees. In some embodiments, the first angle of incidence ranges from about 40 degrees to about 45 degrees. In some embodiments, the first angle of incidence is about 42 degrees. In some embodiments, the second angle of incidence ranges from about 40 degrees to about 70 degrees. In some embodiments, the second angle of incidence ranges from about 62 degrees to about 67 degrees. In some embodiments, the second angle of incidence is about 64 degrees. In some embodiments, the sensor is adapted for sterilization.

  [0023] In some embodiments, the sensor further comprises an optical chassis, the optical chassis having an optical signal generation component, a detection component, a processor, a controller, and a controller when executed by the processor. Directing an optical signal having a first wavelength to interact with the sensing surface at a first angle of incidence to generate a first critical angle signal, and using the detection component, the first critical angle Generating an image of the signal, determining a maximum pixel position of the first critical angle signal on the generated image, and interacting with the sensing surface at a first angle of incidence to generate a second critical angle signal; Directing an optical signal having a second wavelength to act, generating an image of the second critical angle signal using the detection component, and a maximum value of the second critical angle signal on the generated image Let's determine the pixel position of the critical angle And a computer-readable medium comprising instructions for comparing the pixel position of the maximum of the first and second critical angle signal to determine the Rutapikuseru value. In some embodiments, the sensing surface comprises a covered area and an uncovered area, and the first and second critical angle signals are generated from the uncovered area.

  [0024] In some embodiments, the sensor further comprises an optical chassis, the optical chassis having an optical signal generation component, a detection component, a processor, a controller, and a controller when executed by the processor. Directing an optical signal having a first wavelength to interact with the sensing surface at a first angle of incidence to generate a first surface plasmon resonance (SPR) signal, and using a detection component Generating an image of one SPR signal, determining a minimum pixel position of the first SPR signal on the generated image, and generating a second SPR signal at a first angle of incidence with the sensing surface Directing an optical signal having a second wavelength to interact and generating an image of the second SPR signal using the detection component, and generating a minimum value of the second SPR signal on the generated image Pixel position It is determined, and a computer-readable medium comprising instructions for comparing the pixel position of the minimum value of the first and second SPR signal to determine the first SPR delta pixel value.

  [0025] In some embodiments, the computer readable medium, when executed by a processor, causes the controller to interact with the sensing surface at a second angle of incidence to generate a third SPR signal. Directing an optical signal having a wavelength of 1 and using a detection component to generate an image of a third SPR signal, determining a minimum pixel location of the third SPR signal on the generated image; An optical signal having a second wavelength is guided to interact with the sensing surface at a second angle of incidence to generate a fourth SPR signal, and an image of the fourth SPR signal using a detection component , Determine the pixel position of the minimum value of the fourth SPR signal on the generated image, and determine the pixel value of the minimum value of the third and fourth SPR signals to determine the second SPR delta pixel value Compare positions Further comprising a decree.

  [0026] In some embodiments, the sensing surface comprises a covered area and an uncovered area, and the SPR signal is generated from the covered area. In some embodiments, the computer readable medium, when executed by the processor, interacts with the coated area of the sensing surface at a first angle of incidence to generate a first surface plasmon resonance (SPR) signal to the controller. Directing an optical signal having a first wavelength to act, generating an image of the first SPR signal using a detection component, and a pixel of the minimum value of the first SPR signal on the generated image An optical signal having a second wavelength is guided to interact with the sensing surface at a first angle of incidence to determine a position and to generate a second SPR signal, and a second component is used using the detection component. First and second SPR signals to generate a first SPR delta pixel value and to generate a first SPR delta pixel value. Minimum of Further comprising instructions for comparing the pixel position. In some embodiments, the computer readable medium, when executed by the processor, causes the controller to interact with the sensing surface at a second angle of incidence to generate a third SPR signal. And a detection component is used to generate an image of the third SPR signal, a minimum pixel location of the third SPR signal on the generated image is determined, and a fourth Directing an optical signal having a second wavelength to interact with the sensing surface at a second angle of incidence to generate an SPR signal, and using a detection component to generate an image of the fourth SPR signal; Determining the minimum pixel position of the fourth SPR signal on the generated image and comparing the minimum pixel position of the third and fourth SPR signals to determine the second SPR delta pixel value Instruction Further comprising.

  [0027] In some embodiments, the optical signal generation component comprises a laser or a light emitting diode (LED). In some embodiments, the laser or LED emits visible or infrared light. In some embodiments, the laser or LED emits light having a wavelength in the range of about 400 nm to about 1000 nm. In some embodiments, the laser or LED is configured to emit light having a wavelength of about 855 nm. In some embodiments, the laser or LED is configured to emit light having a wavelength of about 950 nm. In some embodiments, the optical chassis further comprises one or more optical signal manipulation components. In some embodiments, the detection component comprises an image sensor. In some embodiments, the image sensor is a charge coupled device (CCD) camera or a scientific complementary metal oxide semiconductor (sCMOS) camera. In some embodiments, the image sensor is an active pixel sensor (APS). In some embodiments, the sensor further comprises a plurality of retention fixtures configured to removably couple the sensor to the optical chassis. In some embodiments, the sensor further comprises an alignment component configured to align the sensor with the optical chassis. In some embodiments, the alignment component comprises a tapered centering component. In some embodiments, the sensor further comprises a plurality of kinematic attachment components.

  [0028] Aspects of the invention include: (i) a sensor comprising a sensing surface comprising an uncovered region, wherein the sensor transmits a first optical signal such that the sensor interacts with the sensing surface at a first angle of incidence. (Ii) an optical signal generation component, a detection component, a processor, a controller configured to direct and direct a second optical signal to interact with the sensing surface at a second angle of incidence; When executed by a processor, causes a controller to direct an optical signal having a first wavelength to interact with a sensing surface at a first angle of incidence to generate a first critical angle signal, and a detection component To generate an image of a first critical angle signal, determine a pixel position of the first critical angle signal on the generated image, and generate a first critical angle signal to generate a second critical angle signal Having a second wavelength to interact with the sensing surface at an angle Directing the signal and using the detection component to generate an image of the second critical angle signal, determining a pixel position of the second critical angle signal on the generated image, and determining a critical angle delta pixel value And an optical chassis comprising a computer readable medium comprising instructions for comparing the pixel positions of the first and second critical angle signals. In some embodiments, the sensing surface comprises a covered area and an uncovered area, and the first and second critical angle signals are generated from the uncovered area.

  [0029] Aspects of the invention provide (i) a sensor comprising a sensing surface with a coated region, wherein the sensor directs a first optical signal such that the sensor interacts with the sensing surface at a first angle of incidence. (Ii) an optical signal generation component, a detection component, a processor, a controller, and a processor configured to direct a second optical signal to interact with the sensing surface at a second angle of incidence. The controller directs an optical signal having a first wavelength to interact with the sensing surface at a first angle of incidence to generate a first surface plasmon resonance (SPR) signal, A detection component is used to generate an image of the first SPR signal, to determine a minimum pixel location of the first SPR signal on the generated image, and to generate a second SPR signal. Interact with the sensing surface at an incident angle of 1 And directing an optical signal having a second wavelength to generate an image of the second SPR signal using the detection component, and a minimum pixel location of the second SPR signal on the generated image And an optical chassis comprising a computer readable medium comprising instructions for comparing the minimum pixel position of the first and second SPR signals to determine the SPR delta pixel value.

  [0030] In some embodiments, the computer readable medium, when executed by a processor, causes the controller to interact with the sensing surface at a second angle of incidence to generate a third SPR signal. Directing an optical signal having a wavelength of 1 and using a detection component to generate an image of a third SPR signal, determining a minimum pixel location of the third SPR signal on the generated image; An optical signal having a second wavelength is guided to interact with the sensing surface at a second angle of incidence to generate a fourth SPR signal, and an image of the fourth SPR signal using a detection component , Determine the pixel position of the minimum value of the fourth SPR signal on the generated image, and determine the pixel value of the minimum value of the third and fourth SPR signals to determine the second SPR delta pixel value Compare positions Further comprising a decree.

  [0031] In some embodiments, the sensing surface comprises a covered area and an uncovered area, and the SPR signal is generated from the covered area. In some embodiments, the computer readable medium, when executed by the processor, interacts with the coated area of the sensing surface at a first angle of incidence to generate a first surface plasmon resonance (SPR) signal to the controller. Directing an optical signal having a first wavelength to act and using the detection component to generate an image of the first SPR signal, and the pixel position of the minimum value of the first SPR on the generated image And determining an optical signal having a second wavelength to interact with the sensing surface at a first angle of incidence to generate a second SPR signal and using the detection component to Generating an image of the SPR signal, determining a minimum pixel location of the second SPR signal on the generated image, and determining the first and the first SPR delta pixel values on the generated image; Second S Further comprising instructions for comparing the pixel position of the minimum value of the R signal.

  [0032] In some embodiments, the computer-readable medium, when executed by a processor, causes the controller to interact with the sensing surface at a second angle of incidence to generate a third SPR signal. Directing an optical signal having a wavelength of 1 and using a detection component to generate an image of a third SPR signal, determining a minimum pixel location of the third SPR signal on the generated image; An optical signal having a second wavelength is guided to interact with the sensing surface at a second angle of incidence to generate a fourth SPR signal, and an image of the fourth SPR signal using a detection component , Determine the pixel position of the minimum value of the fourth SPR signal on the generated image, and determine the pixel value of the minimum value of the third and fourth SPR signals to determine the second SPR delta pixel value Compare positions Further comprising a decree.

  [0033] In some embodiments, the sensor is configured to be removably coupled to the optical chassis. In some embodiments, the system is a bench top system. In some embodiments, the system is a handheld system.

  [0034] Aspects of the invention include a method for determining an osmotic pressure of a sample, the method comprising contacting a sensing surface of a system with a reference medium and generating a first reference surface plasmon resonance (SPR) signal. Directing an optical signal having a first wavelength to interact with the sensing surface at a first angle of incidence to generate, and generating an image of the first reference SPR signal using the detection component; Determining a minimum pixel position of the first reference SPR signal on the generated image and interacting with the sensing surface at a first angle of incidence to generate a second reference SPR signal; Directing an optical signal having a second wavelength; generating an image of a second reference SPR signal using the detection component; and a pixel of a minimum value of the second reference SPR signal on the generated image. Determining the position and the reference medium SPR Comparing the minimum pixel position of the first and second reference SPR signals to determine a filter pixel value, contacting the sensing surface with the sample, and generating a first test SPR signal; Directing an optical signal having a first wavelength to interact with the sensing surface at an angle of incidence of 2; generating an image of the first test SPR signal using the detection component; and Determining the minimum pixel location of the first test SPR signal above, and setting the second wavelength to interact with the sensing surface at a second angle of incidence to generate a second test SPR signal. Deriving an optical signal having, determining a minimum pixel position of a second test SPR signal on the generated image, and first and second tests to determine a test media SPR delta pixel value Comparing the minimum pixel location of the PR signal, comparing the reference media SPR delta pixel value with the test media SPR delta pixel value to generate a first corrected delta pixel value, and determining the osmotic pressure of the sample. Comparing the first corrected delta pixel value with a calibration data set to determine.

  [0035] In some embodiments, the method includes contacting the sensing surface with a reference medium and interacting with the sensing surface at a first angle of incidence to generate a first critical angle signal. Directing an optical signal having a wavelength of 1; generating an image of a first critical angle signal using a detection component; and a pixel position of a maximum value of the first critical angle signal on the generated image Deriving an optical signal having a second wavelength to interact with the sensing surface at a first angle of incidence to generate a second critical angle signal, and using a detection component Generating an image of the second critical angle signal; determining a maximum pixel position of the second critical angle signal on the generated image; and determining a critical angle delta pixel value. Comparing the maximum pixel position of the second critical angle signal and the second critical angle signal; Comparing the first corrected delta pixel value with the critical angle delta pixel value to determine a corrected delta pixel value of the second and the second corrected delta pixel value with the calibration data set to determine the osmotic pressure of the sample. Comparing. In some embodiments, images of the first and second reference SPR signals and the first and second critical angle signals are captured in a single image frame.

  [0036] In some embodiments, the method compares the first or second corrected delta pixel value with an external environment parameter to generate an external environment corrected delta pixel value and determines the osmotic pressure of the sample. Comparing the external environment correction delta pixel value to a calibration data set to do so. In some embodiments, the external environmental parameter is selected from the group comprising temperature, pressure, and humidity.

  [0037] Aspects of the invention include a method for verifying a quality parameter of a sensor, the method contacting a sensing surface of a system with a reference medium and a first reference surface plasmon resonance (SPR) signal. Directing an optical signal having a first wavelength to interact with the sensing surface at a first angle of incidence to generate, and generating an image of the first reference SPR signal using the detection component; Determining one or more characteristics of the first reference SPR signal and comparing one or more characteristics of the first reference SPR signal with a calibration data set to verify a quality parameter of the sensor With. In some embodiments, the sensor quality parameters include the thickness of the translucent film disposed on the sensing surface, the thickness of the adhesive layer disposed on the sensing surface, and the translucent film disposed on the sensing surface. Selected from the group comprising the purity of the material therein and the purity of the material in the adhesive layer disposed on the sensing surface. In some embodiments, the characteristic of the first reference SPR signal is selected from a group comprising the contrast value, shape, or dimension of the first reference SPR signal.

  [0038] Aspects of the invention include a method for verifying a quality parameter of a sensor, the method contacting a sensing surface of a system with a reference medium and generating a first reference critical angle signal Directing an optical signal having a first wavelength to interact with a sensing surface at a first angle of incidence; generating an image of a first reference critical angle signal using a detection component; Determining one or more characteristics of the first reference critical angle signal and comparing one or more characteristics of the first reference critical angle signal to a calibration data set to verify the quality parameters of the sensor; Is provided.

  [0039] In some embodiments, the quality parameter of the sensor includes the thickness of the translucent film disposed on the sensing surface, the thickness of the adhesive layer disposed on the sensing surface, and the thickness disposed on the sensing surface. Selected from the group comprising the purity of the material in the translucent film and the purity of the material in the adhesive layer disposed on the sensing surface. In some embodiments, the characteristic of the first reference critical angle signal is selected from the group comprising the contrast value, shape, or dimension of the first reference critical angle signal. In some embodiments, the optical signal having the first wavelength and the optical signal having the second wavelength are directed to interact with the sensing surface at the same time. In some embodiments, the optical signal having the first wavelength and the optical signal having the second wavelength are directed to interact with the sensing surface in a gated fashion. In some embodiments, the calibration data set is stored in a read-only memory of the system's processor. In some embodiments, the reference medium is air and the sample is tear fluid. In some embodiments, the tear fluid remains in contact with the subject's eye while the method is being performed. In some embodiments, the first angle of incidence is in the range of about 40 degrees to about 45 degrees, and the second angle of incidence is in the range of about 62 degrees to about 67 degrees. In some embodiments, the first angle of incidence is about 42 degrees and the second angle of incidence is about 64 degrees. In some embodiments, the first wavelength is about 855 nm and the second wavelength is about 950 nm.

[0040] A graph showing the relationship between tear osmotic pressure and probability for normal eyes and dry eyes. [0041] Panel A demonstrates a surface plasmon resonance (SPR) technique for measuring tear osmotic pressure. Panel B is a graph showing the relative response as a function of SPR angle. [0042] Panel A is an image generated using a 638 nm wavelength laser. Panel B is an image generated using a conventional LED of 632 nm wavelength. Panel C is a graph showing a greater amount of noise from the laser diode image. Panel D is a graph showing less noise from the LEDs. The graph for panel D is significantly smoother than the graph for panel C. [0043] A graph comparing% reflectance as a function of incident angle for three different optical signals having different wavelengths. Longer wavelength optical signals have narrower (sharper) SPR linewidths. [0044] A diagram of a set of three different images demonstrating differences in image quality for different light sources having different wavelengths. The width of the SPR line is narrower for light with larger wavelengths. [0045] Graph showing the resolution as a function of wavelength for high index glass (SF10, index ~ 1.72) and low index glass (BK7, index ~ 1.52). The graph shows that there is little difference between the different materials. [0046] A graph demonstrating a straight line fitting technique for determining the minimum value of an SPR curve. [0047] SPR line images acquired using a video imager. The region of interest in the image is outlined by the rectangle shown. [0048] FIG. 9 is a graph showing grayscale values as a function of pixel position for the region of interest shown in FIG. A graph was generated corresponding to the average of the vertical column pixel intensities in the region of interest along the X direction. [0049] FIG. 10 is a graph showing the derivative (solid line) of the SPR curve as a function of the SPR curve (dotted line) and the SPR angle (pixel) shown in FIG. The zero crossing of the derivative of the SPR curve is circled. [0050] FIG. 11 is a graph showing the location of the zero crossing of the derivative of the SPR curve shown in FIG. 10 to a fraction of a pixel value. [0051] A graph illustrating the determination of the exact coordinates of a zero crossing using linear interpolation techniques. [0052] A table showing the positions of the SPR minimum values for 10 SPR images acquired sequentially at approximately 1.0 second intervals. [0053] Graph showing relative SPR response for ethanol and deionized water. The pixel location difference for the two media is shown as approximately 910 pixels. [0054] Image showing raw SPR data for ethanol solution. [0055] Image showing raw SPR data for deionized water. [0056] A graph showing osmotic pressure as a function of SPR angle (pixels) acquired and analyzed using differential signal processing techniques. [0057] A graph showing the relative response as a function of pixel count generated using a curve fitting technique. [0058] A graph showing the relative response as a function of pixel count generated by fitting a third order polynomial to an SPR curve. [0059] FIG. 7 shows quadratic and cubic equations that may be used to determine the pixel location corresponding to the SPR minimum. [0060] A graph showing the relative change in refractive index versus temperature for various exemplary materials. [0061] Fig. 15 shows an example of an injection molding sensor. Reference is made to sensors and sensing surfaces. [0062] FIG. 12 is a diagram showing another example of an injection molding sensor. [0063] FIG. 15 is a diagram showing another example of an injection molding sensor. The illustrated sensor interacts with the sensing surface at an incident angle of 42.04 degrees to guide a first optical signal and interacts with the sensing surface at an incident angle of 64.44 degrees to guide a second optical signal. Configured as follows. [0064] FIG. 8 shows another example of an injection molding sensor. The illustrated sensor interacts with the sensing surface at an incident angle of 42.04 degrees to guide a first optical signal and interacts with the sensing surface at an incident angle of 64.44 degrees to guide a second optical signal. Configured as follows. [0065] FIG. 5 shows various optical paths traveling through a plurality of optical chassis components and sensors. [0066] Another view showing various optical paths traveling through a plurality of optical chassis components and sensors. [0067] Panel A is another view showing various light paths traveling through a plurality of optical chassis components and sensors. Panel B is an end view of the sensing surface showing the covered and uncovered areas. Panel C is an enlarged view of the various optical paths that interact with the various facets and sensing surfaces of the sensor. [0068] Panel A uses one LED from the first set of LEDs from the dry sensing surface (in contact with air), SPR lines of air (obtained from the coated area of the sensing surface) and (sensing The figure showing the simulation of the critical angle transition (obtained from the uncovered area of the surface). Panel B shows the SPR line obtained using one LED from the second set of LEDs when the sensing surface is in contact with water or tear fluid. [0069] FIG. 6 shows the Snell's law (the law of refraction) geometry and the critical angle of the substrate. [0070] Graph of reflectivity as a function of angle of incidence for multiple sensing surfaces with different thicknesses of gold film. The critical angle (θ _c ) remains constant and is independent of the thickness of the gold film. [0071] Panel A is another view showing various optical paths traveling through a plurality of optical chassis components and sensors. Panel B is an enlarged view of the various optical paths that interact with the various facets and sensing surfaces of the sensor. [0072] Panel A is a simulated image showing data from a tear sample. Air SPR lines and tear SPR lines and critical angle lines are shown. Panel B is a graph showing gray scale values as a function of pixel position for the image in panel A. The minimum gray scale value corresponding to the air and tear SPR lines and the maximum gray scale value corresponding to the critical angle line are shown. [0073] Another view showing various optical paths traveling through a plurality of optical chassis components and sensors. [0074] Another view showing various optical paths traveling through a plurality of optical chassis components and sensors. [0075] Another view showing various optical paths traveling through a plurality of optical chassis components and sensors. The total length of the illustrated optical chassis is 2.181 inches. [0076] A side view of the optical chassis and sensor. The overall height of the illustrated optical chassis is 0.903 inches. The diameter of the sensor shown is 0.765 inch. [0077] Another side view of the optical chassis and sensor. [0078] Another side view of the optical chassis and sensor. [0079] FIG. [0080] Another side view of the optical chassis and sensor. [0081] Panel A is a side view of the sensor. Panel B is a bottom view of the sensor. [0082] FIG. [0083] Panel A and Panel B are side views of the sensor. [0084] An end view of the sensor. [0085] FIG. 8 is an end view of the sensor and optical chassis. [0086] Illustration of transparent rendering of sensor. [0087] FIG. 6 is a diagram of a bench top system comprising a sensor and an optical chassis comprising various components. [0088] FIG. [0089] Another perspective view of a bench top system. [0090] Image of outer casing components that may be used with the bench top system shown in FIGS.

  [0091] Optical sensors, systems, and methods of use thereof are provided. An aspect of the subject system is to direct a first optical signal to interact with the sensing surface at a first angle of incidence and to interact with the sensing surface at a second angle of incidence. A sensor having a configuration for guiding an optical signal. The subject sensors, systems, and methods find use, for example, in the diagnosis of dry eye disease.

  [0092] Before describing the present invention in more detail, it is to be understood that the invention is not limited to the specific embodiments described and may, of course, vary. Since the scope of the present invention is limited only by the appended claims, the terminology used herein is for the purpose of describing particular embodiments only and is intended to be limiting. It should also be understood that it is not a thing.

  [0093] Where a range of values is provided, the upper and lower limits of the range and any other description within the stated range up to one-tenth of the lower limit unit, unless the context specifically requires otherwise It is understood that each intermediate value between a given value or an intermediate value is encompassed by the present invention. Subject to any particular excluded limits within the stated ranges, the upper and lower limits of these smaller ranges may independently be included within the smaller ranges and are encompassed by the present invention. . Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

  [0094] Certain ranges are presented herein with the term "about" preceding the numerical value. The term “about” is used herein to provide literal support for the exact number that it precedes, as well as a number that is near or approximately equal to the number that the term precedes. In determining whether a number is close to or approximately equal to a specifically listed number, an unenumerated number that is close or approximately equal is substantially equal to the number of the specifically listed number in the context in which it is presented. Can be a number that provides the equivalent.

  [0095] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, exemplary exemplary methods and materials are now described.

  [0096] All publications and patents cited herein are hereby incorporated by reference as if each individual publication or patent was specifically indicated by reference, Incorporated herein by reference to disclose and explain the methods and / or materials from which the publications are cited. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the invention is not entitled to antedate such publication by prior invention. Further, the provided release date may be different from the actual release date and may need to be independently verified.

  [0097] As used herein and in the appended patent specification, the singular forms “a”, “an”, and “the” are particularly well-defined in context. Note that it includes multiple referents unless requested. It is further noted that the claims may be drafted to exclude any optional element. As such, this description serves as an antecedent for the use of exclusive terms such as “alone”, “only”, or the use of “negative” restrictions in connection with the enumeration of claim elements. Is intended.

[0098] As will become apparent to those of ordinary skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein is capable of several other without departing from the scope or spirit of the invention. Having individual components and features that can be easily separated from or combined with any feature of the embodiments. Any recited method may be performed in the order of events recited or in any other order that is logically possible.
Definition
[0099] The term "sensing surface" as used herein refers to the surface of a sensor configured to contact an external medium.

  [00100] The terms "incident angle" or "incident angle" as used interchangeably herein are formed between a beam of light directed to a plane and a line perpendicular to the same plane. Refers to an angle.

  [00101] The term "facet" as used herein refers to a substantially flat portion of a sensor surface (eg, an internal surface or an external surface).

  [00102] The term "translucent film" as used herein refers to a film that is partially transparent to light and facilitates the generation of surface plasmons / polaritons.

  [00103] The terms "reflective coating" and "reflective film" as used interchangeably herein refer to a coating or film that can reflect light or other radiation, respectively. As used herein, the terms “translucent film” and “reflective film” or “reflective coating” are not mutually exclusive, and a given curtain may be both a translucent film and a reflective film.

  [00104] The term "noble metal" as used herein refers to a metallic element that is resistant to corrosion in moist air. Non-limiting examples of noble metals include copper (Cu), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), or combinations thereof.

  [00105] The term "adhesive layer" as used herein is formed on a sensing surface or facet to facilitate adhesion of a coating material (eg, a reflective or translucent film) to the sensing surface or facet Refers to the layer of material to be

  [00106] The term "coating region" as used herein with respect to a sensing surface or facet refers to a region of the sensing surface or facet covered with a coating (eg, a translucent film, a reflective coating, and / or an adhesive layer). Means. The term “uncovered area” as used herein with respect to a sensing surface or facet means an area of the sensing surface or facet that is not covered with a coating.

  [00107] The term "optical chassis" as used herein refers to a structure that supports and / or includes one or more optical components.

  [00108] The term "optical signal" as used herein refers to a signal comprising photons.

  [00109] As used herein, the term "critical angle" refers to the angle of incidence at which total internal reflection occurs at an angle of incidence above it (eg, at an angle of incidence having an angle value greater than the critical angle).

  [00110] As used herein, the term "pixel location" refers to the location of a pixel on a coordinate system, such as, for example, an x, y coordinate plane.

  [00111] The term "compare" as used herein with respect to comparing pixel locations refers to measuring the difference in location of two or more pixels on a coordinate plane. The comparison of pixel locations can be qualitative or quantitative.

  [00112] The term "delta pixel position" as used herein refers to a numerical value that represents the difference in position between two pixels on a coordinate system.

  [00113] The term "external environmental parameter" as used herein refers to a characteristic of the environment that is external to the subject sensor or system. A non-limiting example of an external environmental parameter is the temperature of the room in which the sensor is operated.

  [00114] The term "corrected" as used herein with respect to delta pixel values, for example, corrects delta pixel values for a given parameter (eg, an external environment parameter) that has undergone mathematical manipulation. Refers to a delta pixel value that is being multiplied or divided by a number.

  [00115] As used herein, the term "calibration data set" refers to one or more data points representing a relationship between a measurement standard and a property measured by the subject sensor and / or system. Refers to a set.

  [00116] The term "function" as used herein refers to a mathematical operation that assigns a unique y coordinate value to all x coordinate values.

  [00117] The term "minimum" as used herein refers to the lowest numerical value of a function within an image frame and on a given coordinate system.

  [00118] As used herein, the term "maximum value" refers to the highest numerical value of a function in an image frame and on a given coordinate system.

  [00119] The term "quality parameter" as used herein refers to an aspect of the subject sensor or system that is required for optimal functioning of the sensor or system.

  [00120] As used herein, the term "surface plasmon resonance" or "SPR" refers to the resonance of conduction electrons at the interface between a negative dielectric constant material and a positive dielectric constant material stimulated by incident light. Refers to vibration.

  [00121] As used herein, the term "optical signal manipulation component" refers to a component that can manipulate one or more characteristics of an optical signal. An optical signal manipulation component can include any number of individual components that allow individual components to act in parallel and / or in series to manipulate one or more characteristics of the optical signal. . Non-limiting examples of optical signal manipulation components include beam splitters, spatial filters, filters that reduce external ambient light, lenses, polarizers, and optical waveguides.

  [00122] The term "removably coupled" as used herein refers to connecting two or more components so that the connection is reversible and the components can be separated from each other.

  [00123] As used herein, the term “holding component”. A component that is configured to hold one or more components in a fixed position relative to another component.

  [00124] The term "alignment component" as used herein refers to a configuration configured to provide functional and / or structural alignment between two or more components that are operably coupled. Points to the element.

  [00125] As used herein, the term "kinematic attachment component" refers to an attachment component that provides a number of constraints equal to the number of degrees of freedom in the attached component.

  [00126] As used herein, the term "benchtop system" refers to a system configured to be placed in operation, for example, on a laboratory benchtop, or another suitable substrate surface. Point to.

[00127] The term "handheld system" as used herein refers to a system or component thereof that is configured to be held in a user's hand during operation.
Sensors and systems
[00128] Aspects of the invention include sensors and systems configured to perform the subject method, for example, to determine the osmotic pressure of a sample. In certain embodiments, the subject system has at least one sensing surface, directs a first optical signal to interact with the sensing surface at a first angle of incidence, and a sensing surface at a second angle of incidence. An optical sensor configured to direct the second optical signal to interact with the optical sensor. In some embodiments, the subject system further includes an optical chassis that includes an optical signal generation component and a detection component. Each of these components will now be described in greater detail.
Sensor
[00129] As summarized above, aspects of the present invention include at least one sensing surface, directing a first optical signal to interact with the sensing surface at a first angle of incidence, and second incident A sensor configured to direct the second optical signal to interact with the sensing surface at a corner. By directing the optical signal to interact with the sensing surface at two different angles of incidence, the subject sensor generates data from the sensing surface for two or more different media (eg, air and water) and the same detection The component can be used to detect data. Analysis of the data can then be used to determine one or more characteristics of the media. As such, data obtained from different media can be captured within the same field of view or image frame of the detection component and then analyzed by the detection component. Inclusion of data from the sensing surface for different media within the same field of view or image frame of the detection component can be used in the analysis (e.g., can be used for sensor calibration and / or to analyze unknown samples). ) Provide an internal reference in the data.

  [00130] The subject sensor includes at least one sensing surface comprising a translucent film, the translucent film comprising a noble metal. The translucent film facilitates analysis based on surface plasmon resonance (SPR) of media in contact with the sensing surface. SPR is a phenomenon that occurs when light is incident on a sensing surface at a specific angle so that reflected light is extinguished. At a particular angle of incident light, the intensity of the reflected light exhibits a decreasing intensity characteristic curve that is well defined by a mathematical equation. The angle of incident light corresponding to the minimum reflectance of the curve is affected by the characteristics of the translucent film and the characteristics of the external medium in contact with the translucent film. Panel A of FIG. 2 provides an exemplary overview of the SPR technique for tear osmometry. Panel B of FIG. 2 provides a graph (ie, SPR signal curve, or function) of the SPR signal that demonstrates the relative minimum of the SPR curve and shows the position corresponding to the minimum value of the reflectance of the SPR signal curve. In some embodiments, aspects of the present invention determine the pixel location corresponding to the minimum reflectance of the SPR signal curve represented on the image generated by the detection component (as described further herein). Including deciding.

  [00131] In some embodiments, the translucent film on the sensing surface is about 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 41 nm, 42 nm, 43 nm, 44 nm, 45 nm, 46 nm, 47 nm, 48 nm, 49 nm, 50 nm, 51 nm, 52 nm, 53 nm, 54 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, It can range in thickness from about 0.5 nm to about 200 nm, such as 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, or 195 nm. Any suitable technique, such as a thin film deposition technique (eg, atomic layer deposition (ALD), chemical vapor deposition (CVD), vapor deposition, metal organic chemical vapor deposition (MOCVD), sputtering, etc.), or any of them Using the combination, a translucent film can be deposited on the surface of the sensor. Non-limiting examples of noble metals that can be used in a translucent film in accordance with the subject sensor embodiments include copper (Cu), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), or any combination thereof. In some embodiments, the translucent film on the sensing surface can be composed of a plurality of layers of separate materials, wherein the material in each layer is a noble metal as described above, or any combination thereof (eg, 2 3, 4, 5, 6, 7, or their alloys, such as 8 or more different noble metals. In some embodiments, the sensing surface can comprise a substrate, eg, a microscope slide, having one side that is at least partially coated with a translucent film. In such embodiments, the substrate can be operably coupled to the sensor to provide a sensing surface.

  [00132] In some embodiments, the sensor can include an adhesive layer deposited on the sensing surface between the sensor (or substrate) and the translucent film. The adhesive layer according to embodiments of the present invention serves to promote adhesion of the translucent film to the sensing surface and can modulate one or more characteristics of the optical signal passing through the sensor. For example, in some embodiments, the adhesive layer can comprise a material that improves a desired property of an optical signal passing through the adhesive layer. In some embodiments, the thickness and material composition of the adhesive layer is selected to advantageously manipulate the characteristics of the optical signal passing through the adhesive layer. In some embodiments, a material having a desired refractive index (RI) is selected to modulate the characteristics of the optical signal passing through the adhesive layer. In some embodiments, the adhesive layer comprises a material that modulates the characteristics of the optical signal passing therethrough, eg, reduces the amount of noise in the optical signal.

[00133] In some embodiments, the adhesion layer is about 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, 5.5 nm, 6 nm, 6.5 nm. 7 nm, 7.5 nm, 8 nm, 8.5 nm, 9 nm, 9.5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm 90 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, or 195 nm, etc. About 200 It can range in thickness up to nm. Any suitable technique, such as a thin film deposition technique (eg, atomic layer deposition (ALD), chemical vapor deposition (CVD), vapor deposition, metal organic chemical vapor deposition (MOCVD), sputtering, etc.), or any of them Using the combination, an adhesive layer can be deposited on the surface of the sensor. Non-limiting examples of materials that can be used in the adhesive layer in accordance with the subject sensor embodiments include chromium (Cr), TiO ₂ , TO _x , SiO ₂ , SiO _x , or any combination thereof (eg, they A mixture or alloy).

[00134] Sensing surfaces according to embodiments of the present invention can have any suitable size and shape. In some embodiments, the sensing surface can be a square, rectangular, trapezoidal, octagonal, elliptical, or circular shape, or any combination thereof. The surface area of the sensing surface can vary, and in some embodiments from about 1 mm ^2, such as about 2 mm ² , 3 mm ² , 4 mm ² , 5 mm ² , 6 mm ² , 7 mm ² , 8 mm ² , or 9 mm ^2. It can range up to about 10 mm ² .

  [00135] In certain embodiments, the sensing surface can comprise a covered area and an uncovered area. In some embodiments, the coated area is about 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% , 80%, 85%, 90%, or 95%, etc., with a percentage of the area of the sensing surface ranging from about 10% to 100%. In certain embodiments, the entire sensing surface is coated with a translucent film.

  [00136] A covered region according to an embodiment of the present invention may have any suitable shape. In some embodiments, the coverage area of the sensing surface can be a square, rectangular, trapezoidal, octagonal, elliptical, or circular shape, or any combination thereof. In some embodiments, the sensing surface can comprise a plurality of distinct coverage areas, such as 2, 3, 4, 5, 6, 7, 8, 9, or 10 distinct coverage areas. The coverage area of the sensing surface can be located at any suitable location on the sensing surface. For example, in some embodiments, the covered area may be centered on the sensing surface, and in some embodiments, the covered area may be located, for example, on one particular side of the sensing surface. Can be disposed along one or more sides of the, and so on. In some embodiments, about half of the sensing surface comprises a covered area and about half of the sensing surface comprises an uncovered area. In some embodiments, about 2/3 (about 66%) of the sensing surface comprises a covered area and about 1/3 (about 33%) of the sensing surface comprises an uncovered area. In certain embodiments, the entire surface of the sensing surface is a coated area (ie, 100% of the sensing surface is coated with a translucent film).

  [00137] In some embodiments, the uncovered area of the sensing surface facilitates analysis of the critical angle associated with the sensor. The critical angle is the incident angle at which total internal reflection occurs. The critical angle is affected by the properties of the material from which the sensor is made and is not affected by the external medium that contacts the sensing surface of the sensor. As such, the critical angle of a given sensor can serve as an internal reference during analysis. In some embodiments, aspects of the invention determine a critical angle for a sensor and determine a pixel location corresponding to a critical angle on an image generated by a detection component (described further herein). Determining.

  [00138] Sensors according to embodiments of the present invention can have any suitable size and shape. In some embodiments, the sensor has a semi-cylindrical shape having a plane and a curved surface, and the sensing surface is disposed on the plane. In some embodiments, the sensor comprises a cone shape or a truncated cone shape. In some embodiments, the sensor can have a concave shape such that the sensor comprises an inner surface (eg, an inner surface of the recess) and an outer surface. In some embodiments, the sensor can have a frustoconical concave shape.

  [00139] In some embodiments, the sensor has a length dimension ranging from about 1 cm to about 20 cm, such as 2 cm, 3 cm, 4 cm, 5 cm, 8 cm, 10 cm, 12 cm, 14 cm, 16 cm, or 18 cm. Can do. In some embodiments, the sensor can have a width dimension in the range of about 1 cm to about 20 cm, such as 2 cm, 3 cm, 4 cm, 5 cm, 8 cm, 10 cm, 12 cm, 14 cm, 16 cm, or 18 cm. In some embodiments, the sensor can have a height dimension ranging from about 1 cm to about 20 cm, such as 2 cm, 3 cm, 4 cm, 5 cm, 8 cm, 10 cm, 12 cm, 14 cm, 16 cm, or 18 cm. In some embodiments, the sensor can have a diameter ranging from about 1 cm to about 20 cm, such as 2 cm, 3 cm, 4 cm, 5 cm, 8 cm, 10 cm, 12 cm, 14 cm, 16 cm, or 18 cm.

[00140] In some embodiments, the sensor comprises one or more facets configured to direct the optical signal in a given direction (eg, reflecting from the facet at a given angle). be able to. Facets according to embodiments of the present invention can have any suitable area, and in some embodiments about 5 mm ² , 10 mm ² , 15 mm ² , 20 mm ² , 25 mm ² , 30 mm ² , 35 mm ² , 40 mm. in ^{2, 45mm 2, 50mm 2,} 55mm 2, 60mm 2, 65mm 2, 70mm 2, 75mm 2, 80mm 2, 85mm 2, the range of about 1 mm ² area of up to about 100 mm ^2, such as 90 mm ² or 95 mm ^2, possible. Facets according to sensor embodiments can have any suitable shape, and in some embodiments, in a square, rectangular, trapezoidal, octagonal, elliptical, or circular shape, or any combination thereof possible.

  [00141] A sensor according to an embodiment of the invention may have any suitable number of facets on a given surface of the sensor. For example, in some embodiments, the sensor has a number of facets ranging from 1 to 10, such as 2, 3, 4, 5, 6, 7, 8, or 9, on a given surface of the sensor. Can have. In certain embodiments, the sensor has one or more facets on the inner surface, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 facets on the inner surface. Can have one or more facets on the outer surface, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 facets on the outer surface. In some embodiments, the facets can be coated with a light reflective material to enhance the facet's ability to reflect the optical signal. In some embodiments, the plurality of facets can have different shapes and / or areas. In some embodiments, the plurality of facets can have the same shape and / or area.

  [00142] In certain embodiments, one or more facets may be coated with a reflective coating (eg, a reflective film, or an optical reflective material). In some embodiments, all of the sensor facets may be coated with a reflective coating. In some embodiments, certain facets of the sensor are coated with a reflective coating, and other facets on the same sensor are not coated with a reflective coating. In some embodiments, the entire surface of the selected facet can be coated with a reflective coating. In some embodiments, only a portion or section of a particular facet surface is coated with a reflective coating. In a preferred embodiment, a plurality of “shoulder” facets are coated with a reflective gold coating. For example, in one preferred embodiment, the facets labeled in FIG. 43 (as well as facets placed symmetrically on the opposite side of the sensing surface) are coated with a reflective coating (eg, a reflective gold coating).

  [00143] In some embodiments, the reflective coating on the facet surface is about 0.5 nm, about 1 nm, about 5 nm, about 10 nm, about 20 nm, about 30 nm, about 40 nm, about 50 nm, about 60 nm, about 70 nm. About 80 nm, about 90 nm, about 100 nm, about 150 nm, about 200 nm, about 250 nm, about 300 nm, about 350 nm, about 400 nm, about 450 nm, about 500 nm, about 550 nm, about 600 nm, about 650 nm, about 700 nm, about 750 nm, about The thickness may range from about 0.1 nm to about 1000 nm (1 μm), such as 800 nm, about 850 nm, about 900 nm, or about 950 nm, or thicker. Any suitable technique, such as a thin film deposition technique (eg, atomic layer deposition (ALD), chemical vapor deposition (CVD), vapor deposition, metal organic chemical vapor deposition (MOCVD), sputtering, etc.), or any of them A reflective coating can be deposited on the surface of the facet, such as using a combination. Non-limiting examples of noble metals that can be used in the reflective film in accordance with the subject sensor embodiments include copper (Cu), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium ( Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), or any combination thereof. In a preferred embodiment, the reflective coating comprises gold (Au).

  [00144] In some embodiments, the sensor can include an adhesive layer deposited on one or more facets and disposed between the sensor (or substrate) and the reflective coating on the facets. The adhesive layer according to embodiments of the present invention serves to promote adhesion of the reflective coating on the facets and can modulate one or more characteristics of the optical signal reflected from the facets. For example, in some embodiments, the adhesive layer can comprise a material that improves the desired properties of the optical signal reflected from a particular facet. In some embodiments, the thickness and material composition of the adhesive layer is selected to advantageously manipulate the characteristics of the optical signal reflected from a particular facet.

[00145] In some embodiments, the adhesion layer is about 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, 5.5 nm, 6 nm, 6.5 nm. 7 nm, 7.5 nm, 8 nm, 8.5 nm, 9 nm, 9.5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm 90 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, or 195 nm, etc. About 200 It can range in thickness up to nm. Any suitable technique, such as a thin film deposition technique (eg, atomic layer deposition (ALD), chemical vapor deposition (CVD), vapor deposition, metal organic chemical vapor deposition (MOCVD), sputtering, etc.), or any of them Using the combination, an adhesive layer may be deposited on the surface of the sensor (eg, on the facet of the sensor). Non-limiting examples of materials that can be used in the adhesive layer in accordance with the subject sensor embodiments include chromium (Cr), TiO ₂ , TO _x , SiO ₂ , SiO _x , or any combination thereof (eg, they A mixture or alloy).

  [00146] In some embodiments, the sensor is configured to communicate one or more identification information to another component of the system (eg, to an optical chassis component, to a processor, etc.). An identification component can be included. For example, in some embodiments, the sensor is, for example, a type of translucent film disposed on the sensing surface of the sensor, a configuration of covered and uncovered regions on the sensor's sensing surface, a configuration of facets in the sensor An identification component that provides information to the optical chassis can be included. In some embodiments, the system is configured to respond to identification information communicated by the sensor. For example, in certain embodiments, the system receives identification information from a sensor and configures the system to perform a particular analysis method in response (eg, one or more having a particular wavelength). The system may be configured to generate an optical signal. An identification component according to embodiments of the present invention can have any suitable configuration and can include, for example, a bar code, a magnetic strip, a computer readable chip, and the like. A system according to embodiments of the present invention may be configured with a corresponding identification component configured to receive and / or identify identification information from an identification component on the sensor.

  [00147] An aspect of the subject sensor includes a holding component configured to hold the sensor in a fixed position relative to another component of the subject system (eg, an optical chassis described further below). Including. Retention components according to embodiments of the present invention can have any suitable shape and dimensions, for example, can take the form of tabs or flanges that extend from one or more portions of the subject sensor. In some embodiments, the sensor can include a holding component configured to removably couple the sensor to another component, such as, for example, an optical chassis. In some embodiments, the sensor can allow the operator to achieve coupling of the sensor to the optical chassis without compromising the sterility of the sensor, and uncoupling the sensor from the optical chassis without physical contact with the sensor. Is configured to removably couple and / or uncouple to the optical chassis in a non-contact or aseptic manner, meaning that it can be made possible.

  [00148] An aspect of the subject system includes one or more sensor mounting components configured to facilitate aseptic operation of the sensor as well as coupling (eg, removable coupling) of the sensor to the optical chassis. Including. For example, in certain embodiments, the sensor mounting component holds the sensor in a sterile manner, allows a user to couple the sensor to the optical chassis, and then leaves the sensor coupled to the optical chassis in a sterile manner. Configured to be detached from the sensor. Sensor mounting components according to embodiments of the present invention can have any suitable dimensions, and in some embodiments include a surface that is complementary to at least a portion of the sensor. In some embodiments, the sensor mounting component is at least a portion of the outer surface of the sensor to prevent the coated portion of the sensor from accessing the external environment until the sensor mounting component is removed from the sensor. Configured to cover. In some embodiments, the sensor mounting component is adapted for sterilization by any suitable technique and is adapted to maintain its function after sterilization is complete. Sterilization techniques are well known in the art and include, for example, heat sterilization, gamma irradiation, chemical sterilization (eg, ethylene oxide gas sterilization), and many others. Aspects of the invention include sensor mounting components that are adapted for sterilization without changing their function in any recognizable manner. In some embodiments, the sensor mounting component is configured to allow sterilization of the sensor while the sensor and the sensor mounting component are coupled to each other.

  [00149] The subject sensor embodiments include one or more kinematic attachment components configured to provide a number of constraints equal to the number of degrees of freedom of the attached components. For example, for a three-dimensional object with six degrees of freedom, a kinematic attachment component that provides six constraints can be used to mount a sensor on an optical chassis (described further below).

  [00150] A subject sensor aspect includes one or more alignment components configured to align the sensor with one or more components of an optical chassis (discussed further below). In some embodiments, the alignment component can comprise a tapered centering component that aligns the sensor with the optical chassis.

  [00151] The subject sensors can be made from any of a variety of suitable materials, including but not limited to glass, optical grade plastics, polymers, combinations thereof, and the like. Non-limiting examples of suitable materials include polymethyl methacrylate (PMMA), polycarbonate (PC) polystyrene (PS) cycloolefin polymer (eg, ZEONEX® E48R), sapphire, diamond, quartz, zircon (zirconia) Or any combination thereof. In some embodiments, the materials used to make the subject sensors are 1.21, 1.22, 1.23, 1.24, 1.25, 1.26, 1.27, 1 .28, 1.29, 1.3, 1.31, 1.32, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.4 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, 1.47, 1.48, 1.49, 1.5, 1.51, 1.52, 1 .53, 1.54, 1.55, 1.56, 1.57, 1.58, 1.59, 1.6, 1.61, 1.62, 1.63, 1.64, 1.65 1.66, 1.67, 1.68, 1.69, 1.7, 1.71, 1.72, 1.73, 1.74, 1.75, 1.76, 1.77, 1. .78, 1.79, 1.8, 1.81 1.82, 1.83, 1.84, 1.85, 1.86, 1.87, 1.88, 1.89, 1.9, 1.91, 1.92, 1.93, 1. The refractive index can range from about 1.2 to about 2.0, such as 94, 1.95, 1.96, 1.97, 1.98, or 1.99. One skilled in the art will recognize that any material with suitable optical properties can be used in the subject sensor. Sensors according to embodiments of the present invention may be manufactured using any suitable technique, such as machining, 3D printing, and / or molding (eg, injection molding). In some embodiments, the sensor can be manufactured using a suitable technique and then one or more compositions (eg, translucent film, adhesive layer, or reflective coating) on the surface of the sensor. It can be further processed to deposit. In some embodiments, the sensor is disposable and can be discarded after one or more uses. In some embodiments, the sensor is adapted for repeated use, eg, washed and sterilized after use and then adapted for use again.

  [00152] As discussed above, aspects of the invention allow data from the sensing surface for two different test media (eg, air and water) to be captured within the same field of view or image frame of the detection component. The first optical signal is guided to interact with the sensing surface at the first incident angle, and the second optical signal is guided to interact with the sensing surface at the second incident angle. Includes sensors. In some embodiments, the sensor interacts with the sensing surface over a first narrow range of incident angles to generate data within the same field of view or image frame of the detection component, as discussed above. And directing the second optical signal to interact with the sensing surface over a second narrow range of incident angles. In some embodiments, the narrow range of incident angles is a power ranging from about 2 degrees to about 10 degrees, such as about 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, or 9 degrees. Over.

  [00153] Without being bound by theory, the range of first and second angles of incidence selected for the sensor is determined by the optical properties of the material used to manufacture the sensor, as well as the external to be analyzed by the sensor. Depends on the medium. As such, the first and second incident angles, or the first and second narrow ranges of incident angles, may be different for sensors made of different materials, and the range of incident angles for a given sensor is analyzed. It can be based on the expected refractive index of the medium. In some embodiments, the sensor is configured to have a dynamic range of incidence angles of clinical significance, the sensor facilitates analysis of the sample and data having clinical significance (eg, diagnosis of dry eye disease) Configured to direct one or more optical signals to interact with the sensing surface over a range of incident angles providing data. Those skilled in the art will appreciate that different first and second angles of incidence or ranges thereof generate data within the same field of view of the sensing component from the sensing surface for different test media (eg, air and water, air and tears, etc.). For example, based on the optical properties of the material used to manufacture the sensor, the properties of the external medium that is contacted with the sensing surface, the properties of the translucent film, and / or the properties of the adhesive layer (if present) It will be understood that it can be selected.

  [00154] In some embodiments, the sensor, when coupled to an optical chassis (described below), is formed into a benchtop system configured for use in a laboratory environment, eg, a clinical laboratory environment. Can be done. In some embodiments, the sensor may be formed in a handheld system when coupled to an optical chassis (described below). In a preferred embodiment, the handheld system has dimensions similar to the dimensions of the pen. In use, the handheld system can be held by a physician, for example, and contacted with the sample being analyzed.

  [00155] In some embodiments, the sensor is adapted for sterilization by any suitable technique and is adapted to maintain its function after sterilization is complete. Sterilization techniques are well known in the art and include, for example, heat sterilization, gamma irradiation, chemical sterilization (eg, ethylene oxide gas sterilization), and many others. Aspects of the invention include sensors that are adapted for sterilization without changing their function in any recognizable manner.

  [00156] Aspects of the invention include a kit that includes a plurality of sensors. In some embodiments, the kit can include multiple identical sensors. In some embodiments, the kit can include two or more sensors (eg, a plurality of first types of sensors and a plurality of second types of sensors) having different characteristics. Kits according to embodiments of the present invention can comprise any suitable packaging, such as hermetic packaging (eg, hermetic packaging), vacuum hermetic packaging, and the like. In certain embodiments, the kit can be sterile (eg, the contents of the kit are sterile and the kit packaging is configured to maintain the sterility of the contents). In some embodiments, the kit can comprise a plurality of sensors, each individual sensor being sealed separately in aseptic packaging. In some embodiments, the kit is not sterile but is adapted for sterilization so that the kit can be sterilized at the point of use, eg, in a clinician's office or hospital. In some embodiments, the kit can further include one or more sensor mounting components, as described herein.

  [00157] In some embodiments, the sensor is storage stable and can be stored for extended periods of time, such as one to two years or more, while maintaining its functionality. In certain embodiments, the sensor can be provided in a kit with appropriate packaging so that the sensor remains storage stable for extended periods of time. For example, in some embodiments, the sensor can be provided in hermetic packaging or vacuum sealed packaging to facilitate storage stability for extended periods of time.

  [00158] In one preferred embodiment, the sensor is made from a cycloolefin polymer and has a frustoconical concave shape having an inner surface and an outer surface, and the sensor is a sensing surface disposed on the outer surface. And two facets on the inner surface and four facets on the outer surface, the facets directing a first optical signal to interact with the sensing surface at an incident angle of about 42 degrees, and about 64 It is configured to direct the second optical signal to interact with the sensing surface at an incident angle of degrees. In this preferred embodiment, data from both air and water, or data from both air and tears, can be collected within the same field of view or image frame of the detection component, and thereby used in the analysis. Provide an internal reference in the image.

  [00159] In another preferred embodiment, the sensor is made from a cycloolefin polymer and has a frustoconical concave shape having an inner surface and an outer surface, and the sensor is disposed on the outer surface of the sensor. Along with the sensing surface, it comprises two facets on the inner surface and four facets on the outer surface so that the facets interact with the sensing surface over a narrow range of incident angles ranging from about 40 degrees to about 45 degrees. And directing the second optical signal to interact with the sensing surface over a narrow range of incident angles ranging from about 62 degrees to about 67 degrees.

  [00160] Referring now to FIG. 22, a diagram of a sensor according to one embodiment of the present invention is provided. The illustrated embodiment is an injection molded transparent plastic sensor having a sensing surface with a gold film.

  [00161] FIG. 23 is a diagram of another sensor according to an embodiment of the present invention. In the illustrated embodiment, the sensor comprises a gold film sensing surface. The upper part of the illustrated sensor functions as an SPR prism. The middle portion of the illustrated sensor is a skirt portion and the lower portion of the illustrated sensor is a base portion that connects to an optical chassis (described further below).

  [00162] FIG. 24 is another view of a sensor according to an embodiment of the present invention. In the illustrated embodiment, the sensor is configured to direct the first optical signal to interact with the sensing surface at an incident angle of about 42.04 degrees, and with the sensing surface at an incident angle of about 64.44 degrees. It is configured to direct the second optical signal to interact.

  [00163] FIG. 25 is another view of a sensor according to an embodiment of the present invention. In the illustrated embodiment, the sensor is configured to direct the first optical signal to interact with the sensing surface at an incident angle of about 42.04 degrees, and with the sensing surface at an incident angle of about 64.44 degrees. It is configured to direct the second optical signal to interact. Further shown is a gold coating on the sensing surface, an oval outer surface of the sensor, an optional curved lower surface of the sensor, a point source LED, and a beam splitter.

  [00164] Panel A of FIG. 42 is a side view of a sensor according to an embodiment of the present invention having a frustoconical concave shape having an inner surface and an outer surface. In the illustrated embodiment, the outer surface of the sensor has four reflective facets and a tapered centering component that mates with the optical chassis. Panel B is a bottom view of the sensor, showing two facets on the inner surface of the sensor. A retention component and a kinematic attachment component are also shown.

  [00165] FIG. 43 is a perspective view of the sensor shown in FIG. Multiple holding fixtures are visible, as well as the sensing surface and four facets on the outer surface of the sensor.

  [00166] Panel A of FIG. 44 is a side view of a sensor according to an embodiment of the present invention having a frustoconical concave shape having an inner surface and an outer surface. In the illustrated embodiment, the outer surface of the sensor has four reflective facets and a tapered centering component that mates with the optical chassis. Panel B is a side view of the sensor, showing broken lines showing the flow of material through the mold during the process of manufacturing the sensor. The kinematic attachment position is also shown.

  [00167] FIG. 45 is a top end view of a sensor according to an embodiment of the present invention. The illustrated sensor includes a sensing surface comprising a covered area and an uncovered area. Three holding components or tabs configured to removably couple the sensor to the optical chassis are also shown.

[00168] FIG. 47 is a perspective perspective view of a sensor according to an embodiment of the present invention.
Optical chassis
[00169] As summarized above, aspects of the present invention include an optical chassis comprising an optical signal generation component and a detection component. In some embodiments, the optical chassis can comprise an optical signal manipulation component. Each of these aspects is described in more detail below.

  [00170] Aspects of the invention include one or more optical signal generation components configured to generate an optical signal. In some embodiments, the optical signal generation component can include a light source that generates an optical signal, such as, for example, a laser, a light emitting diode (LED), a point source LED, or a white light source with a spectral filter. In some embodiments, the optical chassis includes a number of optical signal generation components in the range of 1-10, such as 2, 3, 4, 5, 6, 7, 8, or 9 optical signal generation components. Can be included.

  [00171] An optical signal generation component according to embodiments of the present invention may be configured to generate light having any suitable wavelength ranging from UV light to visible light, infrared light (eg, any May have a suitable emission spectrum). In some embodiments, the optical signal is about 325, 350, 375, 387, 393, 400, 425, 433, 445, 450, 467, 475, 488, 490, 492, 494, 495, 500, 502, 505, 510, 516, 517, 520, 525, 545, 550, 567, 573, 574, 575, 585, 596, 600, 603, 605, 611, 625, 633, 645, 650, 655, 667, 670, 673, 675, 690, 694, 700, 725, 750, 775, 800, 825, 850, 855, 875, 900, 925, 940, 950, 975, 1000, 1025, 1033, 1050, 1060, 1075, 1100, 1125, 1150, 1175, 1200, 1225, 1250, 12 0,1275,1300,1325,1350,1375,1400,1425,1450 or the like 1475 nm,, it may have a wavelength in the range of about 300nm~ about 1500 nm. In some embodiments, the optical signal can have a wavelength of about 855 nm. In some embodiments, the light source can have a wavelength of about 950 nm.

  [00172] An optical signal generation component according to embodiments of the present invention may be configured to generate an optical signal in various ways. For example, in some embodiments, the optical signal generation component is configured to continuously generate an optical signal. In some embodiments, one or more optical signal generation components may be configured to simultaneously generate optical signals having two different wavelengths. In some embodiments, the optical signal generation component is configured to generate a flashing optical signal that can be measured in a gated fashion. In some embodiments, the optical signal generation component is configured to generate an optical signal having a single wavelength. In some embodiments, the optical signal generation component generates multiple optical signals having different wavelengths so that the same optical signal generation component can generate two or more different wavelength optical signals. Configured as follows.

  [00173] In some embodiments, the optical chassis comprises optomechanical components configured or adapted to place physical obstacles in the path of one or more optical signals. The physical obstacle creates one or more reference signals that can be detected and analyzed by the detection component. In some embodiments, the optomechanical component is a vertical or horizontal in one or more optical signals such that vertical or horizontal shadows or occluded areas of the optical signal can be detected by the detection component. Can be configured to create an obstacle. In some embodiments, the optomechanical component is vertically and vertically within one or more optical signals such that a combination of vertical and horizontal shadows or occluded areas of the optical signal can be detected by the detection component. It can be configured to create a horizontal obstacle combination. In some embodiments, the optomechanical component is circular or elliptical in one or more optical signals such that a circular or elliptical shadow or occluded region of the optical signal can be detected by the detection component. It can be configured to create a shape obstacle.

  [00174] Aspects of the invention include a detection component configured to detect one or more optical signals from a subject sensor and generate data therefrom. In some embodiments, the detection component is configured to detect one or more optical signals from the subject sensor and generate an image of the data (eg, a digital image) for analysis. In some embodiments, the detection component is configured to generate multiple images from one or more optical signals. In some embodiments, the detection component generates multiple images per second, such as 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 or more per second. Composed. In some embodiments, the detection component comprises a video recording component (eg, a video camera) configured to generate a video of one or more optical signals received from the sensor. In some embodiments, the detection component is configured to capture one or more image frames of the video and perform further processing on the one or more image frames, as further described below. .

  [00175] A detection component according to an embodiment of the invention is configured to receive an optical signal as input and direct the optical signal to a detector for analysis. In some embodiments, the detection component may be configured to allow only a specific wavelength of light or only a specific wavelength range of light to enter the detection component. For example, in some embodiments, the detection component can include one or more optical filters configured to allow only light in a particular wavelength range to enter the detection component.

  [00176] In some embodiments, the detection component can include one or more detectors comprising a photodiode. A photodiode according to an embodiment of the invention is configured to absorb photons of light and convert the light into a current that can be measured. In some embodiments, the photodiode may include one or more optical filters, lenses, or any other suitable component that can be used to convert light energy into current for measurement. Good.

  [00177] In some embodiments, the detection component can include one or more photomultiplier tubes (PMTs). A PMT according to an embodiment of the invention is configured to detect incident photons by multiplying the current generated by the incident optical signal.

  [00178] In some embodiments, the detection component comprises one or more avalanche photodiodes (APDs), or single photon avalanche photodiodes (SPADs), also known as Geiger mode avalanche photodiodes or G-APDs. Can be included. APDs and SPADs according to embodiments of the present invention detect optical signals (such as low intensity signals) down to a single photon level by utilizing photon triggered avalanche currents in a semiconductor device to detect incident electromagnetic radiation. can do.

  [00179] In some embodiments, the detection component operates by converting the time profile of the light pulse into a spatial profile on the detector by causing a time-varying deflection of the light pulse across the detector. One or more streak cameras can be included.

  [00180] In some embodiments, the detection component can include one or more detectors having an image sensor. An image sensor according to an embodiment of the present invention is configured to convert an optical image into an electronic signal. Examples of image sensors include, but are not limited to, charge coupled devices (CCD) and complementary metal oxide semiconductor (CMOS) or N type metal oxide semiconductor devices. In some embodiments, the image sensor may be an active pixel sensor (APS).

  [00181] In some embodiments, the detection component can include one or more cameras. In some embodiments, the camera is a CCD camera or scientific CMOS that provides extremely low noise, high frame rate, wide dynamic range, high quantum efficiency (QE), high resolution, and large field of view. It is a camera (sCMOS). Such cameras are commercially available from science and technology vendors.

  [00182] In some embodiments, the detection component can include one or more linear array sensors (LAS). A linear array sensor according to an embodiment of the present invention measures the incident light over a defined exposure time and produces a voltage or digital output representative of the exposure of each pixel in the array. With an array. LAS is well known in the art and is generally available in various dimensions and pixel resolution (DPI). In some embodiments, the analog output of the LAS can be interfaced directly to an analog-to-digital converter (ADC) to perform digital signal processing.

  [00183] In some embodiments, the detection component generates an image of one or more optical signals received from the subject sensor, and the plurality of images are organized on a coordinate system in the imaging array. Configured to be converted or rendered into a digital image comprising a plurality of pixels. In some embodiments, the digital image can have a two-dimensional coordinate system, eg, an x, y coordinate system associated with it, and each pixel in the digital image is assigned an x, y coordinate. In certain embodiments, the detection component can generate a grayscale digital image, and each pixel in the digital image is assigned a grayscale value corresponding to a monochrome tone ranging from white to black. In some embodiments, the detection component can generate a color digital image, and each pixel in the digital image is assigned a color. In some embodiments, the number of pixels in the x direction of the imaging array ranges from about 500 to about 4000 or more, such as about 1000, 1500, 2000, 2500, 3000, or 3500 or more. In some embodiments, the number of pixels in the y direction of the imaging array ranges from about 500 to about 4000 or more, such as about 1000, 1500, 2000, 2500, 3000, or 3500. Any detection component capable of generating an image from one or more signals received from the subject sensor may be used in accordance with the subject system and method.

  [00184] Aspects of the subject system include an optical signal manipulation component configured to manipulate one or more characteristics of the optical signal. Examples of optical signal manipulation components include, but are not limited to, mirrors, lenses (eg, cylindrical lenses, double lenses, collimating lenses), beam splitters, prisms (eg, beam translation prisms), diffraction gratings, photomultiplier tubes. Optical filters (eg, long pass filters that can reduce or eliminate ambient light, baffle components, etc., optical filters that reduce external ambient light, for example), beam shaping optics, optical waveguides, polarizers, spatial filters / Includes spatial apertures. An optical signal manipulation component according to embodiments of the present invention, in some embodiments, includes any suitable component that includes a plurality of the same individual components (eg, a plurality of photomultiplier tubes, a plurality of polarizers, etc.). A number of individual components can be included.

  [00185] In some embodiments, aspects of the subject system include one or more spatial apertures. A spatial aperture (also known as a spatial filter) according to embodiments of the present invention is a component configured to remove aberrations in a light beam due to imperfections or variations in one or more optical components of the system. is there. In some embodiments, the spatial aperture is disposed in the optical path of the optical signal to shield the light corresponding to the undesirable portion or structure of the optical signal while allowing the desired portion of the optical signal to pass through the aperture. Includes apertures or openings to allow. Spatial apertures according to embodiments of the present invention can include small circular or “pinhole” apertures that allow light to pass through. In some embodiments, the spatial aperture has an aperture in the range of 50 μm to 500 μm, such as 100, 150, 200, 250, 300, 350, 400, or 450 μm in diameter. In certain embodiments, the spatial aperture may include an aperture whose size is variable, and the subject method may include changing the size of the spatial aperture (eg, changing the diameter). In certain embodiments, the spatial aperture may include an aperture whose size may vary from 50 μm to 500 μm, such as 100, 150, 200, 250, 300, 350, 400, or 450 μm.

  [00186] In certain embodiments, the optical signal manipulation component may be used to shape the optical signal from the light source to create a collimated optical signal. In certain embodiments, one or more optical components may be used to shape the optical signal into a collimated optical signal. For example, in some embodiments, a light collimating lens or collection of lenses can be placed in the path of the light signal and used to shape the light signal from the light source into a collimated light signal.

  [00187] In some embodiments, the optical signal manipulation component can include one or more polarizers configured to polarize the optical signal. The polarization can be p-polarization (ie, transverse magnetic (TM) polarization), or s-polarization (ie, transverse electrical (TE) polarization), or any combination thereof. In some embodiments, the optical signal manipulation component can include an elliptical polarizer and / or a circular polarizer configured to polarize the optical signal.

  [00188] Aspects of the invention include a controller, a processor, and a computer-readable medium configured or adapted to control and / or operate one or more components of a subject system or sensor. . In some embodiments, the system communicates with one or more components of the subject system or sensor as described herein, eg, one or more methods described herein. To perform, includes a controller configured to control aspects of the system and / or perform one or more operations or functions of the subject system. In some embodiments, the system includes a processor and a computer readable medium that may include a memory medium and / or a storage medium. Applications and / or operating systems embodied as computer readable instructions (or “firmware”, ie, permanent software programmed into read-only memory) on a computer readable memory include, but are not limited to, Performing one or more of the described method steps, acquiring and processing data obtained from the subject sensors and / or systems, and / or one or more algorithms or other on the data for analysis Can be performed by the processor to provide some or all of the functionality described herein. In some embodiments, the firmware can include instructions for performing one or more image capture sequences that capture one or more images of the media placed in contact with the sensing surface. In some embodiments, the system processes one or more images, analyzes data from one or more images (eg, to determine the osmotic pressure of a test sample), or Software including instructions for executing one or more algorithms that may be used for any combination thereof may be included. In some embodiments, the system may be configured to automatically perform one or more methods. For example, in some embodiments, the system may respond to certain events, such as coupling of a sensor to the optical chassis, receiving user input (eg, receiving an activation signal from a user), etc. Or it may be configured to automatically execute multiple image capture sequences and / or image or data processing algorithms.

  [00189] In some embodiments, the system receives a user interface, such as a graphical user interface (GUI), and / or input from the user and performs one or more of the methods described herein. One or more user input devices adapted or configured to. In some embodiments, the GUI is configured to display data or information to the user.

  [00190] In some embodiments, the system is configured with one or more temperatures configured to control the temperature of one or more portions of the sensor and / or one or more components of the optical chassis. Contains control elements. For example, in some embodiments, the system includes a temperature controller configured to maintain the sensor or optical chassis within a target temperature range. Temperature control elements according to system embodiments may include resistance heaters, thermoelectric heaters or coolers, fans, and the like.

  [00191] In some embodiments, the system includes one or more environmental analysis components configured to measure one or more characteristics of the external environment. For example, in some embodiments, the system can include a temperature sensor (eg, a thermometer or thermocouple) that can measure the temperature of the environment. In some embodiments, the system can include a pressure sensor (eg, a barometer) that can measure the pressure (eg, barometric pressure) of the environment. In some embodiments, the system can include a humidity sensor (eg, hygrometer, humidity sensor) that can measure the humidity of the external environment. In certain aspects, the subject system is configured to consider or correct for one or more characteristics of the external environment when analyzing the sample. For example, in some embodiments, the processor is configured to consider, for example, external temperatures when analyzing a sample.

  [00192] Aspects of the subject system are also configured to establish a connection that can be used to exchange / transmit data between two or more components of the system, eg, USB port, Ethernet (registration) Data exchange functions, such as a trademark port or other data port. The subject system aspects also include a wireless transmission component, such as a WiFi component, configured to wirelessly transmit data between two or more components of the system. For example, in some embodiments, the system can send data obtained from sensors to a database or repository for storage.

  [00193] Aspects of the subject system can also include one or more computer processors, data storage, and / or database components that can be used to store and / or analyze data acquired by the subject system. May be included. Such a component may be physically connected to other components of the subject system, eg, via a USB connection, or the subject system, eg, via a WiFi connection or via the Internet. It may be configured to communicate wirelessly with other components. In some embodiments, the computer processor, data storage, and / or database components of the subject system may be remotely located, eg, located at a physical location that is different from the physical location of the sensor. Also good.

  [00194] Aspects of the subject system may also include one or more power components, such as batteries and / or power cables, configured to provide power to the subject system. Power components according to embodiments of the present invention may be modular and may be configured to be removably coupled to the subject system for the purpose of providing power, eg, the subject system One or more batteries or battery packs configured to be inserted into or otherwise coupled to. In some embodiments, the subject system includes a power cable configured to establish electrical contact with a standard power outlet. In some embodiments, the system can include a base unit configured to recharge one or more components of the system (eg, the optical chassis or components thereof).

  [00195] In some embodiments, the system can include one or more disinfecting components configured to sanitize one or more components of the system. For example, in some embodiments, the system can include a UV light disinfection component configured to illuminate one or more portions of the system with UV light. In some embodiments, the disinfecting component may be placed in a base unit configured to recharge one or more components of the system as described above.

  [00196] In some embodiments, various features of the subject system include a single housing that includes a housing formed from a suitable material, such as a plastic, metal, glass, or ceramic material, and any combination thereof. Formed in the device. For example, in some embodiments, as described herein, a system that includes a sensor and an optical chassis is formed from a plastic housing, and various additional components of the system are disposed within the housing. . In some embodiments, the system is formed into a single benchtop system that can be used to perform the subject method, as further described below. In some embodiments, the system is formed into a single handheld system that can be carried by the user. In certain embodiments, the handheld system is wireless. In certain embodiments, the handheld system includes a rechargeable battery component. In a preferred embodiment, the system features are formed in a wirelessly rechargeable pen-sized device that can be used to perform the methods described herein.

  [00197] In one preferred embodiment, the optical chassis includes four point source LEDs as the optical signal generating component, two of the point source LEDs emitting light having a wavelength of about 855 nm. Configured, two of the point source LEDs are configured to emit light having a wavelength of about 950 nm. In one preferred embodiment, the optical chassis has approximately 2592 × 1944 active pixels, determines the light intensity value at each pixel, and assigns a grayscale value to each pixel, thereby converting the incident light into a digital electronic signal. A CMOS digital image sensor for converting to

  [00198] Aspects of the invention include one or more signal processing components configured to analyze data obtained from the detection components. For example, in some embodiments, the signal processing component is configured to identify a region of interest (ROI) in the image generated by the detection component. In some embodiments, the signal processing component is configured to generate a mathematical function corresponding to the average pixel intensity along a given coordinate direction of the image. For example, in some embodiments, the signal processing component is configured to calculate an average vertical column pixel intensity for each pixel location along the x coordinate of the image and generate a mathematical function that represents the result. The Once generated, the mathematical function can be analyzed, for example, to determine the x-coordinate corresponding to the relative minimum or relative maximum of the mathematical function.

  [00199] In certain embodiments, the signal processing component is configured to apply one or more noise reduction techniques that serve to reduce or remove noise from the signal. For example, in some embodiments, the signal processing component is configured to apply a Gaussian blur algorithm to reduce noise in the signal. In some embodiments, the signal processing component is configured to use differential signal processing to accurately locate the zero crossing value of the differential signal.

  [00200] Referring now to FIG. 26, an optical chassis and sensor according to an embodiment of the present invention is shown. In this figure, the various light paths starting from the LED and traveling through the system are shown. The illustrated embodiment includes LED light sources with wavelengths of 855 nm and 950 nm and a 5-facet sensor. In addition, the illustrated optical chassis includes a doublet lens, a cylindrical lens, a beam folding mirror, and a detection component.

  [00201] FIG. 27 illustrates another optical chassis and sensor according to an embodiment of the present invention. In this figure, the various light paths starting from the LED and traveling through the system are shown. The illustrated embodiment includes an LED light source with wavelengths of 855 nm and 950 nm and a sensor. In addition, the illustrated optical chassis includes a cylindrical lens, a doublet lens, and a detection component.

  [00202] Panel A of FIG. 28 shows another optical chassis and sensor according to an embodiment of the present invention. In this figure, two light paths starting from the LED and traveling through the system are shown. The illustrated embodiment includes light sources with wavelengths of 855 nm and 950 nm (each light source comprises two sets of LEDs), a sensor having a plurality of internal and external facets, and a sensing surface. In addition, the illustrated optical chassis includes a cylindrical lens, a collimating lens, and a detection component. Panel B shows a top end view of the sensing surface of the illustrated sensor. The sensing surface comprises a coated region having a gold coating (eg, a gold translucent film coating) disposed in a rectangular orientation along the center line of the sensing surface. On either side of the covered area, the sensing surface comprises an uncovered area. Panel C shows the sensor and its internal facet (n = 2) (labeled with circled numbers 1 and 7), its external facet (n = 4) (circled number 2, Figure 3 shows an enlarged view of the sensing surface (labeled with the circled number 4), as labeled 3, 5, and 6).

  [00203] Panel A in FIG. 32 shows another optical chassis and sensor according to an embodiment of the present invention. In this figure, the various light paths starting from the LED and traveling through the system are shown. The illustrated embodiment includes an LED light source with wavelengths of 855 nm and 950 nm and a sensor. In addition, the illustrated optical chassis includes a cylindrical lens, a doublet lens, and a detection component. Panel B shows sensor inner facet (n = 2) (labeled with circled numbers 1 and 5), sensor outer facet (n = 2) (circled numbers 2 and 4). And an enlarged view of the sensing surface labeled with the circled number 3. In the illustrated embodiment, facet 2 is not coated, facet 4 is coated with a reflective coating, and sensing surface 3 is coated with a translucent film.

  [00204] FIG. 34 illustrates another optical chassis and sensor according to an embodiment of the present invention. In this figure, the various light paths starting from the LED and traveling through the system are shown. The illustrated embodiment includes an LED light source with wavelengths of 855 nm and 950 nm and a sensor. In addition, the figure shows the position of the cylindrical lens, collimating lens, optical wedge, and detection component (eg, XIMEA® imager).

  [00205] FIG. 35 shows a side view of an optical chassis and sensor according to an embodiment of the present invention. In this figure, the various light paths starting from the LED and traveling through the system are shown. The illustrated embodiment includes an LED light source with wavelengths of 855 nm and 950 nm and a sensor. In addition, the figure shows a cylindrical lens, a collimating lens, an optical wedge, and a detection component (eg, XIMEA® imager). In this illustrated embodiment, the sensor is operably coupled to the optical chassis.

  [00206] FIG. 36 shows a side view of an optical chassis and sensor according to an embodiment of the present invention. In the illustrated embodiment, the length of the optical chassis is approximately 2.181 inches.

  [00207] FIG. 37 shows a side view of an optical chassis and sensor according to an embodiment of the present invention. In the illustrated embodiment, the height of the optical chassis is about 0.903 inches and the sensor diameter is about 0.765 inches.

  [00208] FIG. 38 shows a side view of the optical chassis and sensor shown in FIG. In the illustrated embodiment, in the illustrated embodiment, the optical chassis includes a collimating lens, a cylindrical lens, an optical wedge, and a detection component (eg, a XIMEA® imager).

  [00209] FIG. 39 shows a side view of an optical chassis and sensor according to an embodiment of the present invention. In this illustrated embodiment, the optical chassis includes a chassis window, two cylindrical lenses, a beam splitter, LEDs with wavelengths of 850 nm and 940 nm, an optical wedge, and a detection component (eg, XIMEA® imager). ).

  [00210] FIG. 40 is a perspective view of an optical chassis and sensor according to an embodiment of the present invention. In the illustrated embodiment, the optical chassis includes LEDs at 850 nm and 940 nm wavelengths, sensor cap locking components, polarizers and barrels, control boards, and detection components (eg, XIMEA® imager assembly). Including.

  [00211] FIG. 41 is a side view of an optical chassis and sensor according to an embodiment of the present invention. In the illustrated embodiment, the optical chassis includes LEDs with wavelengths of 850 nm and 940 nm, a polarizer and barrel, a control board, a detection component (eg, a XIMEA® imager assembly), and an optical chassis component. And a surrounding case (LacriPen case).

  [00212] FIG. 46 is a top end view of the sensor removably coupled to the optical chassis. In the illustrated embodiment, a sensing surface of a sensor comprising a coated surface (gold coated region) and an uncoated surface (uncoated prism region) is shown. The illustrated sensor also includes three retaining components or retaining tabs configured to removably couple the sensor to the optical chassis. The illustrated sensor is configured to twist lock with the optical chassis.

  [00213] FIG. 48 is a diagram of a bench top system according to an embodiment of the present invention. In this illustrated embodiment, the system includes a semi-cylindrical sensor, a gold-coated microscope slide, an image sensor, a beam splitter, LED light sources and collimators with wavelengths of 950 nm and 855 nm, and a circuit board. The illustrated embodiment is arranged in a square housing and is configured to be placed in use, for example, on a laboratory bench top.

  [00214] FIG. 49 is a perspective view of the bench top system shown in FIG.

  [00215] FIG. 50 is a labeled perspective view of the bench top system shown in FIGS. 48 and 49. FIG. The illustrated embodiment shows a semi-cylindrical sensor, a gold-coated microscope slide, an image sensor, a beam splitter, LEDs with wavelengths of 950 nm and 855 nm, and a circuit board.

[00216] FIG. 51 is an image of a housing and associated cover plate that may be used to house the bench top system shown in FIGS.
how to use
[00217] Aspects of the invention include a method of analyzing a sample using the subject sensor system, for example, to determine the osmotic pressure of the sample. As shown in FIG. 1, the average osmotic pressure of tears in normal eyes is different from the average osmotic pressure of tears in dry eye and can therefore serve as a diagnostic predictor of dry eye disease. The subject method includes a medium (e.g., a reference medium or a sample having an unknown osmotic pressure) whose sensory surface is to be tested for a period of time sufficient to perform one or more of the subject methods. ). In some embodiments, the subject method includes 80 seconds, 70 seconds, 60 seconds, 50 seconds, such as 0.5 seconds, 0.4 seconds, 0.3 seconds, 0.2 seconds, or 0.1 seconds or less. It can be performed within a time period that is 90 seconds or less, such as seconds, 40 seconds, 30 seconds, 20 seconds, 10 seconds, 5 seconds, 4 seconds, 3 seconds, 2 seconds, or 1 second or less. In some embodiments, the subject method performs a diagnostic analysis on a patient's bodily fluid (eg, a patient's tear film) and a condition or disorder (eg, dry eye disease) based on the results of the analysis. ) Is diagnosed. For example, in some embodiments, a patient is diagnosed with dry eye disease if it is determined that the patient's tear film has an osmotic pressure value within a certain range.

  [00218] A method aspect has a first wavelength to interact with a sensing surface of a sensor at a first angle of incidence to generate a signal (eg, an SPR signal or a critical angle signal) in response. It involves guiding an optical signal. In some embodiments, the method includes directing one or more optical signals having different wavelengths to interact with the sensing surface at a first angle of incidence while the sensing surface is in contact with the sample. Accompany. In some embodiments, the method contacts the sensing surface with a reference medium and directs first and second optical signals having different wavelengths to interact with the sensing surface at a first angle of incidence. And then contacting the sensing surface with the test medium and directing first and second optical signals having different wavelengths to interact with the sensing surface at a second angle of incidence.

  [00219] A method aspect involves measuring a critical angle signal and an SPR signal generated from a sensing surface. The SPR signal is generated by directing the optical signal to interact with the coated area of the sensing surface. The critical angle signal is generated by directing the optical signal to interact with the uncovered area of the sensing surface. In some embodiments, the method directs first and second optical signals having different wavelengths to interact with the coated area of the sensing surface to generate first and second SPR signals. Accompanied by. In some embodiments, the method includes first and second optical signals having different wavelengths to interact with uncovered areas of the sensing surface to generate first and second critical angle signals. With guiding.

  [00220] In some embodiments, the method involves directing an optical signal to interact with the sensing surface at one or more angles of incidence. For example, in some embodiments, the method directs a first optical signal to interact with the sensing surface at a first angle of incidence and interacts with the sensing surface at a second angle of incidence. Leading a second optical signal. In some embodiments, the method involves directing one or more optical signals to interact with the sensing surface at different angles of incidence, depending on the type of medium contacted with the sensing surface. For example, in some embodiments, the method includes contacting one or more of the sensing surface with a first medium (eg, a reference medium) and interacting with the sensing surface at a first angle of incidence. Directing the optical signal; then contacting the sensing surface with a second medium (eg, a test medium); and one or more optical signals to interact with the sensing surface at a second angle of incidence. With guiding.

  [00221] In certain embodiments, the method involves directing optical signals of different wavelengths to interact with the sensing surface. As discussed above, the subject system is configured to generate an optical signal having any wavelength in the range of about 300 nm to about 1500 nm. In some embodiments, the method involves generating a first optical signal having a wavelength of about 855 nm and generating a second optical signal having a wavelength of about 950 nm. In some embodiments, multiple optical signals can be directed to interact simultaneously with the sensing surface. For example, in some embodiments, two or more optical signals having different wavelengths are directed to interact simultaneously with the sensing surface. In some embodiments, multiple optical signals may be directed to interact with the sensing surface in a gated fashion.

  [00222] Aspects of the method involve signal processing of one or more signals (eg, one or more SPR signals and / or critical angle signals) received from the sensing surface. In some embodiments, the system includes signal processing capabilities configured to process the signal prior to analysis. For example, in some embodiments, the method involves processing the signal to reduce noise prior to analysis. In some embodiments, the method involves applying a Gaussian blur algorithm to the signal to reduce the amount of noise in the signal. In some embodiments, the method involves applying low pass filtering to the signal to reduce the amount of noise in the signal.

  [00223] Aspects of the method involve detecting a signal using a detection component. In some embodiments, the detection component is configured to generate an image based on the signal received from the sensing surface. In some embodiments, the detection component is configured to generate a plurality of images from one or more signals received by the imaging component. For example, in some embodiments, the detection component is configured to generate multiple images per second after a sample (eg, a reference medium or test medium) is placed in contact with the sensing surface of the sensor. . In some embodiments, the detection component is configured to generate multiple images per second, such as 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 or more images per second. The In some embodiments, the detection component is configured to generate a video of one or more optical signals received from the sensor. In some embodiments, the detection component is configured to capture one or more image frames of the video and perform further processing on the one or more image frames, as further described below. .

[00224] In some embodiments, the detection component has a field of view, and an image can be generated from a region of interest (ROI) within the field of view. In certain embodiments, the method involves capturing data from multiple signals from a sensing surface within a single image frame. Capturing data from multiple signals within a single image frame provides an internal reference that can be used in the analysis of the sample
[00225] Aspects of the method involve data processing of images generated from the detection component. In some embodiments, the data processing involves applying a coordinate system (eg, x, y coordinate system) to the image. In some embodiments, each pixel in the generated image, or a portion thereof, may be assigned specific x, y coordinate values. In some embodiments, each pixel in the image may be assigned a numerical value related to the light intensity or color at the pixel. For example, in some embodiments, each pixel in the image is assigned a grayscale value. In some embodiments, each pixel in the image is assigned a color value. In some embodiments, data processing involves performing mathematical operations on a plurality of pixels. For example, in some embodiments, data processing involves calculating an average grayscale value for a plurality of pixels. In some embodiments, data processing involves calculating an average grayscale value for a column of pixels at a particular x coordinate on the image.

  [00226] Aspects of the method involve generating a mathematical function based on data captured in the image using the detection component. For example, in some embodiments, data from an image can be processed and converted into a function that can be mathematically analyzed and manipulated using standard techniques. In some embodiments, the image is analyzed by determining the average grayscale value of the column of pixels at each x coordinate, and the resulting data is a function or curve that mathematically represents the signal from which the data was obtained. Is converted to Once generated, the function can be mathematically analyzed or manipulated to determine its properties.

  [00227] In some embodiments, the function may be analyzed to determine a minimum or maximum value using standard techniques. For example, in some embodiments, the derivative of a function can be determined and used to calculate the relative minimum or maximum of the function. In some embodiments, the function can be smoothed using standard techniques, thereby reducing or reducing noise in the data.

  [00228] Aspects of the method involve analyzing a function derived from the SPR signal to identify pixel locations that correspond to the minimum of the function. The minimum value of the function corresponds to the minimum reflectivity of the SPR signal and can be used in analyzing the sample (eg, determining the osmotic pressure of the sample).

  [00229] Aspects of the method involve analyzing a function derived from the critical angle signal to identify the pixel location corresponding to the maximum value of the function. The pixel position corresponding to the maximum value of the function can be used to determine the critical angle of the sensor.

  [00230] In some embodiments, an aspect of the method involves analyzing data obtained from a reference signal created by an optomechanical component. For example, in some embodiments, the optomechanical component (as described above) creates a reference signal that can be analyzed to determine one or more parameters of the sample. In certain embodiments, the reference signal generated by the optomechanical component is generated when the sensing surface of the sensor is contacted with the sample, or a plurality of different samples (eg, air sample and water sample, air sample and tear film) When touched by a sample, etc.), changes in the SPR minimum (eg, the number of pixels by which the SPR minimum is moved or shifted) can be used as a fixed reference signal that can be measured against it. In certain embodiments, the reference signal created by the optomechanical component is used as a fixed reference signal that can be compared across different sample types (eg, air and water, air and tear film, water and tear film, etc.) Can be done.

  [00231] Aspects of the method involve comparing pixel locations corresponding to various features of the mathematical functions described above. For example, in some embodiments, the method uses a minimum pixel position of a function derived from a first SPR signal to determine a SPR delta pixel value, a function derived from a second SPR signal. With a comparison of the minimum pixel position. The SPR delta pixel value represents the distance between the minimum values of the first and second SPR signals. In some embodiments, the method derives the maximum pixel position of the function derived from the first critical angle signal from the second critical angle signal to determine the critical angle delta pixel value. It involves comparing with the pixel position of the maximum value of the function. The critical angle delta pixel value represents the distance between the maximum values of the first and second critical angle signals.

  [00232] In some embodiments, the method involves mathematically manipulating the delta pixel values to account for one or more external conditions that can affect the operation of the subject sensor. For example, in some embodiments, the method involves multiplying or dividing the delta pixel value by a correction factor to account for external conditions. As discussed above, in some embodiments, the subject system can include an environmental analysis component that can be used to measure one or more characteristics of the environment in which the sensor is operating. .

  [00233] In some embodiments, the method involves verifying a quality parameter of the sensor. For example, in some embodiments, one or more characteristics of the signal generated by the sensor are evaluated to determine whether the sensor is of sufficient quality for use. In some embodiments, one or more characteristics of the SPR signal are evaluated to determine if the sensor is of sufficient quality for use. In certain embodiments, the contrast value, shape, or dimension (eg, height, width, or depth) of the SPR signal (or a data set or function derived therefrom) is sufficient for the sensor to use. Evaluated to determine if it is quality. In some embodiments, one or more characteristics of the critical angle signal are evaluated to determine if the sensor is of sufficient quality for use. In certain embodiments, the contrast value, shape, or dimension (eg, height, width, or depth) of the critical angle signal (or data set or function derived therefrom) is sufficient for the sensor to use. Evaluated to determine if it is of good quality. In some embodiments, the method includes a sensor having, for example, a sufficiently thick translucent film and / or adhesive layer on the sensing surface, or a sufficiently pure material in the translucent film and / or adhesive layer Can be used to verify whether it has.

  [00234] Aspects of the method use one or more delta pixel values (eg, one or more corrected delta pixel values) to determine a sample characteristic (eg, sample osmotic pressure) calibration data set. With a comparison. In some embodiments, the system can include multiple calibration data sets that can be used for different purposes. In some embodiments, the system includes a calibration data set that includes an osmotic pressure value as a function of the delta pixel value, and the method compares the delta pixel value to the calibration data set to determine the osmotic pressure of the sample. With that. In some embodiments, the system includes a calibration data set that includes quality parameter values and the method generates a signal generated by the sensor to determine whether the sensor is of sufficient quality for use. Of comparing one or more characteristics of the to a calibration data set. In some embodiments, the system includes a calibration data set that includes correction factors for various external environment parameters, and the method uses the measured external environment parameters as a calibration data set to determine an appropriate correction factor. Comparing and then mathematically manipulating the delta pixel values to apply correction factors.

  [00235] In some embodiments, the method involves operably connecting a sensor to the optical chassis. In certain embodiments, the method involves removably coupling the sensor to the optical chassis, performing the analysis method described herein, and then removing the sensor from the optical chassis. In some embodiments, the method involves aseptically coupling the sensor to the optical chassis. In some embodiments, the method involves aseptically uncoupling the sensor from the optical chassis.

  [00236] Aspects of the method involve analysis of any suitable sample. In some embodiments, the sample is a gaseous or liquid medium. In certain embodiments, the medium can be a calibration medium having a known osmotic pressure value. For example, in some embodiments, the method contacts the sensor with a medium having a known osmotic pressure, directs one or more optical signals to interact with the sensing surface, and results therefrom. Detecting one or more signals that occur as (eg, detecting an SPR signal or a critical angle signal). In some embodiments, the sample can be a reference medium (eg, a test medium or a medium to which the sample will be compared). In some embodiments, the reference medium can be air (eg, air in a room where the sensor is used). In some embodiments, the sample can be a liquid medium, such as water. In some embodiments, the sample can be a bodily fluid (eg, tear fluid from the subject's eye). In some embodiments, the method comprises contacting the sensing surface of the sensor with the sample and maintaining contact between the sample and the sensing surface while at least some of the method steps are performed. Accompany.

  [00237] In a preferred embodiment, the method contacts the sensing surface of the sensor with air as the reference medium and interacts with the sensing surface at an incident angle of about 42 degrees to generate a first SPR signal. Leading a first optical signal having a wavelength of about 855 nm. The first SPR signal is detected using a detection component that generates an image from the signal. The image of the signal is processed to generate a mathematical function that represents the first SPR signal. The pixel location corresponding to the minimum value of the function is determined.

  [00238] Next, a second optical signal having a wavelength of about 950 nm is directed to interact with the sensing surface at the same incident angle of about 42 degrees to generate a second SPR signal. The second SPR signal is detected using a detection component that generates an image from the signal. The image of the signal is processed to generate a mathematical function that represents the second SPR signal. The pixel location corresponding to the minimum value of the function is determined. The pixel locations corresponding to the minimum values of the first and second SPR signals are then compared to determine a reference media SPR delta pixel value.

  [00239] Next, the sensing surface of the sensor is placed in contact with the tear film of the subject. A first optical signal having a wavelength of about 855 nm is directed to interact with the sensing surface at an incident angle of about 64 degrees to generate a third SPR signal. The third SPR signal is detected using a detection component that generates an image from the signal. The image of the signal is processed to generate a mathematical function that represents the third SPR signal. The pixel location corresponding to the minimum value of the function is determined.

  [00240] Next, a second optical signal having a wavelength of about 950 nm is directed to interact with the sensing surface at the same incident angle of about 64 degrees to generate a fourth SPR signal. The fourth SPR signal is detected using a detection component that generates an image from the signal. The image of the signal is processed to generate a mathematical function that represents the fourth SPR signal. The pixel location corresponding to the minimum value of the function is determined. The pixel locations corresponding to the minimum values of the third and fourth SPR signals are then compared to determine the test media SPR delta pixel value.

  [00241] The reference media SPR delta pixel value is then compared to the test media SPR delta pixel value to determine a corrected delta pixel value. The corrected delta pixel value is compared to a calibration data set that includes a plurality of data representing the relationship between the osmotic pressure and the corrected delta pixel value to determine the osmotic pressure of the sample.

[00242] The following examples are provided to aid the understanding of the present invention, the true scope of which is set forth in the appended claims. It will be understood that changes may be made in the procedures described without departing from the scope of the invention.
Example 1: Reduction of optical noise in a sensor using a point light source LED
[00243] Reduction of optical noise has been achieved in the system by using a point source LED as an optical signal generation component. FIG. 3 shows that 638 nm laser diodes have substantially higher optical noise than red LEDs (632 nm nominal wavelength), as shown graphically in each of the charts on the right side of their corresponding SPR images. It is clearly shown. The use of point source LEDs instead of laser diodes thus reduced optical noise in the system.
Example 2: Optimizing the resolution of SPR signal measurement
[00244] As shown in FIG. 4, longer wavelength optical signals produce a narrower SPR linewidth. FIG. 5 shows the narrowing of SPR lines with increasing wavelengths, as verified experimentally using a simple SPR setup on an optical table. The decrease in SPR linewidth with increasing wavelength is readily apparent to the naked eye.

  [00245] Since the SPR minimum angular shift decreases at longer wavelengths, it was unclear whether a narrower SPR linewidth at longer wavelengths would provide higher SPR resolution in the subject system. Thus, the calculation of the refractive index change by 0.001 refractive index unit (“RIU”) and the SPR minimum angle shift Δθ relative to the full width at half maximum (“FWHM”) of the SPR line was calculated by Robert M. . This was performed using an online SPR calculator (http://unicorn.ps.uci.edu/calculations/freshnel/fcform.html) provided by Professor Corn's research group. The ratio of these two quantities (ie Δθ / FWHM) was defined as the SPR resolution. The result of the calculation was that the improvement in resolution at a wavelength of 950 nm was in the range of 4-5 times compared to 635 nm. These calculations are also negligible in the resolution obtained using either high index glass (SF10, n to 1.72) or low index glass (BK7, n to 1.52) (see FIG. 6). It also showed that there was a difference that could be made.

[00246] Prior to these calculations, a common scientific folklore was that high index prisms provided substantially better SPR performance than low index prisms. As a result, optical plastics generally have a relatively low refractive index, so this established scientific folklore has prevented the use of injection molded optical plastics as disposable SPR prisms. Thus, based on the above calculations, injection molded optical plastics can be used as disposable SPR prisms in the subject sensors and systems, thereby reducing commodity costs.
Example 3: Differential signal processing
[00247] The measurement of tear osmotic pressure up to 1.0 mOsm corresponds to the determination of the refractive index of tears up to about 10 ^-5 RIU. A general engineering rule of thumb is that the accuracy of the measurement should exceed the target accuracy by about 10 times. Therefore, in the tears osmolarity measurement device, it is desirable to have a final refractive index accuracy 1RIU about ^10-6 minutes.

  [00248] Various techniques for determining the location of the SPR line minimum are well known in the art. One technique is to fit a straight line to the falling and rising edges of the SPR line and is shown in FIG. A brief description of the technique is found in US Pat. No. 7,395,103, the disclosure of which is hereby incorporated by reference in its entirety. Another technique described as the centroid method is also disclosed in US Pat. No. 7,395,103.

  [00249] It is well known that the point where the derivative of a function is zero represents either a local maximum or a local minimum of the function. Since any real-world data contains noise, scientific folklore rejects the use of derivatives to find either the maximum or minimum of real-world data. The general belief is that taking the derivative of noisy data will result in unacceptable noise in the derivative data, thus making it impossible to accurately locate the differential zero crossing. Is to do.

  [00250] In practice, there are three effects that can counteract the effects of differential signal processing noise to find the exact position of the SPR curve minimum. The first is to start with a very low noise SPR line image. Here, this was achieved by careful optical design and using LEDs rather than lasers for the light source. Second, the movement from a visible light source to a near infrared light source results in a fairly narrow SPR line with a rapid rate of change in intensity near the SPR minimum, resulting in a large differential signal for any noise in the signal. . Finally, any residual noise in the image of the SPR line can be minimized by appropriate low pass filtering. Here, a Gaussian blur algorithm was used to reduce any residual noise to an acceptable level.

  [00251] FIG. 8 shows a typical SPR line image obtained using a 855 nm point source LED as the light source. The images were acquired using a 640x480 video imager. The images were imported into the application ImageJ image processing software developed at the National Institutes of Health. Next, a 25 pixel Gaussian blur was applied to the image and an appropriate region of interest was defined for the image, as indicated by the rectangle in FIG. Within this region of interest (“ROI”), a plot profile was generated corresponding to the average of the vertical column pixel intensities in the image along the X direction. The result of these operations is shown in FIG. 9, which is an ImageJ plot profile of the region of interest. Finally, the data from the plot profile curve can be generated using well-known mathematical techniques to find the positive zero crossing of the derivative that accurately defines the position of the SPR line minimum (as shown in FIG. 10). Can be numerically differentiated using. It should be noted that the differential curve shown in FIG. 10 is actual data derived from the SPR image in FIG. The derivative curve is very smooth and does not show obvious noise artifacts.

  [00252] In practice, due to the low level of noise in the differential data, the zero crossing of the derivative of the SPR line can be located within a fraction of the pixel using interpolation techniques. FIG. 11 shows the relative value of the derivative of the SPR image in FIG. Note that the derivative has little noise and over a limited range of 220-230 pixels, the derivative is approximately linear. A zero crossing of the derivative occurs between pixel 224 and pixel 225 at the coordinates of (224, −0.2943) at pixel 224 and at the coordinates of (225, 0.1922) at pixel 225. From these values, the exact coordinates of the zero crossing can be determined by linear interpolation, as shown in the geometry shown in FIG. In this example, the zero crossing occurs exactly at the coordinates (244.6049, 0.0).

[00253] FIG. 13 shows the position of the SPR minimum for 10 SPR images acquired sequentially at approximately 1.0 second intervals. SPR setups or other tests between each image acquisition other than time so that variations in the location of the SPR minimum are mainly due to random optical and electronic noise present in each acquired image There was no change in conditions. The image represented by these data was acquired using an Aptina MT9P031 5 megapixel grayscale image sensor consisting of 2592 horizontal x 1944 vertical 2.2 μm square pixels. The separate calibration step shown in FIG. 14 required measuring the SPR line minimum pixel position for ethanol and deionized water corresponding to a separation of about 910 pixels. The difference in refractive index between these two liquids is Δn = 1.35713 (ethanol) −1.3288 (deionized water) = 0.28333. The result that Δn per pixel is 3.113 × 10 ⁻⁵ RIU (FIG. 14). Raw SPR images for the SPR lines of ethanol and deionized water used in this calibration are shown in FIGS. 15 and 16, respectively.

[00254] Returning to FIG. 13, the overall range of zero crossings over 10 samples is the entire range of 0.2662 pixels or ± 0.1331 pixels relative to the average pixel value. This corresponds to an overall uncertainty of refractive index of ± 4.143 × 10 ⁻⁶ R.

  [00255] FIG. 17 shows SPR osmotic pressure data acquired and analyzed using the differential signal processing described above. A series of five precisely calibrated saline solutions were measured using a miniature optical breadboard SPR instrument consisting of a gold coated high index glass SPR prism, an 855 nm point source LED, and an Aptina MT9P031 5 megapixel image sensor. . Data captured using this breadboard and processed using differential signal processing techniques demonstrated an accuracy of ± 1.0 mOsm over the osmotic pressure range of 295 mOsm to 348.5 mOsm. Saline was independently calibrated using a freezing point depression osmometry technique that also has a defined accuracy of ± 1.0 mOsm. Clearly, the agreement between the freezing point depression method and the SPR technique is within the limits of experimental error.

[00256] An alternative approach using low-pass filtering (eg, Gaussian blur) for noise reduction in differential signal processing is to use curve fitting in the region of the SPR minimum to average the noise in the SPR image. Is to use. FIG. 18 is an SPR line used to demonstrate this approach to differential signal processing. It should be noted that the SPR line profile in FIG. 18 is clearly asymmetric, and the slope on the left side of the SPR minimum is substantially smaller (and opposite in sign) than the slope on the right side of the minimum. is there. While it is attractive to consider fitting the minimum of the SPR line minimum to a parabola, in practice this results in poor fit and low R ² values. The result is that the location of the zero crossing found in this way deviates from the actual position of the SPR minimum. A more accurate approach is to fit the cube to the SPR line near its minimum, as shown in FIG. In general, this results in an R ² value close to 1. As further illustrated in FIG. 20, the resulting cubic equation can then be differentiated, set to zero, and solved using the quadratic equation to find the location of the SPR minimum.
Example 4: Self-calibrating sensor theory
[00257] SPR-based analysis can provide a very accurate measurement of the refractive index change of a medium (eg, gas or liquid) in contact with the external gold surface of the SPR prism. With appropriate caution, the change in the refractive index in the range of 1RIU of 10 ^-6 min may be obtained in the laboratory under carefully controlled conditions (see Figure 13). The premise of using SPR for tear osmolarity measurement is that the tear osmotic pressure and tear refractive index are linearly related. The linearity of the osmotic pressure of physiological saline is shown to be within the range of ± 5.0 mOsm to ± 1 mOsm and the measurement accuracy within the range of ± 4 10 ^-6 RIU. Is quite linear. Data showing the linearity of ± 1.0 mOsm for some accurate saline is shown in FIG.

  [00258] Accurately fitting a straight line to a series of precisely calibrated saline is much easier than the problem of accurately and precisely determining the salinity (ie, refractive index) of an unknown saline It should be noted that this is a problem. The first case simply requires the determination of the slope of the calibration curve. The second case requires determining both the slope and the y intercept point. Without the help of an external reference solution, this second case is very difficult to achieve. External reference solutions are not practical because the gold sensitive surface of the SPR instrument is very susceptible to contamination.

[00259] FIG. 13 provides data from which RIU per pixel can be calculated, -Δn = 1.35713-1.3288 = 0.02853 RIU corresponds to 910 pixels, or Δn / pixel = 3. 113 × 10 ⁻⁶ RIU / pixel. The slope of the osmotic pressure vs. pixel count chart in FIG. 17 is 0.7257 pixels / mOsm. Multiplying these two coefficients together results in a calibration constant of 1.0 mOsm = 2.25 × 10 ⁻⁵ RIU. Typically, an industry rule of thumb is that the calibration accuracy of any measurement should be about 10 times better than the desired accuracy required within a single measurement. Therefore, the absolute calibration accuracy required to accurately measure ± 1.0 mOsm tear osmotic pressure requires the SPR device calibration accuracy to be ± 2.25 × 10 ⁻⁶ RIU. Note that this is a higher calibration accuracy than that demonstrated by the reproducible data in FIG. 13 as obtained under controlled laboratory conditions. This means that reliable tear osmotic pressure measurements with an accuracy of ± 1.0 mOsm can be difficult to obtain in routine practice.

[00260] FIG. 21 shows the relative change in refractive index with temperature (ie, Δn / Δt) for several common optical plastics. ZEONEX® E48R (“E48R”), a low birefringence optical plastic manufactured by Zeon Corporation (Japan), which has a refractive index of 1.523 in the near infrared, is suitable for molding optical SPR prisms. Note that it is an optical polymer. Note that E48R has a Δn / Δt similar to that of the other optical plastics shown in FIG. 21, which is approximately 1.269 × 10 ⁻⁴ RIU / ° C. As a result, the refractive index change of ZEONEX® E48R per degree Celsius is approximately 28 times greater than the resolution required to accurately and reproducibly measure osmotic pressures up to ± 1.0 mOsm ( That is, 1.269 × 10 ⁻⁴ ÷ 4.50 × 10 ⁻⁶ ). In practice, this means that the temperature of the E48R SPR prism must be maintained or measured within an accuracy of about 0.036 ° C. Neither of these conditions is feasible to achieve in a normal clinical office environment. Therefore, very accurate temperature calibration means are required to achieve the desired accuracy of tear osmotic pressure measurement.
Example 5: Self-calibrating sensor concept 1
[00261] The basic self-calibrating SPR sensor concept evolved from the diagrams of FIGS. FIG. 22 shows an integral injection molded sensor formed in optical grade plastic. This integral sensor concept uses a kinematic mounting feature to constrain to 6 degrees of freedom to ensure that each and every sensor is accurately and repeatably aligned with the optical chassis of the system. Was intended. As shown in FIG. 23, this concept consists of a base portion that provides a precise kinematic mechanical interface to the optical chassis, a gold (or protected silver) coated SPR sensing surface for measuring tear osmotic pressure. Assume a sensor consisting of three segments: an SPR prism portion having, and finally, a “skirt” portion to provide a transition between the SPR prism portion and the base portion. The prism portion preferably appears at both the optical critical angle signal transition and the air SPR line at two separate wavelengths of about 850 nm and 950 nm, as well as when the gold-coated sensor surface of the SPR prism is wetted by tear fluid. Self-calibration is provided by performing a method to obtain another separate SPR line that was supposed to be.

  [00262] FIG. 24 illustrates the concept of an SPR sensor that uses an elliptical surface to image light from an LED light source onto a sensing surface. As shown in FIG. 25, approximately 42.0 ° to generate air SPR lines and tear SPR lines to allow generation of both air SPR lines and tear (or water) SPR lines. There must be light incident on the sensing surface at about 64.4 ° which produces This is accomplished by imaging light from a point source LED using an elliptical surface to relay the image of the LED onto a sensing surface (eg, a gold-coated sensing surface) of a transparent elliptical reflector. . The incident angle of the LED light on the inner elliptical surface is such that total internal reflection occurs for the LED light. The light reflected by the gold-coated SPR sensing surface is then reflected by the left hand oval inner surface towards the point source LED and blocked by a beam splitter that reflects the return light to the image sensor that detects the position of the SPR line. The For the case of a rotationally symmetric elliptical sensor, the SPR line is actually an SPR circle centered on the rotational axis of the elliptical surface.

[00263] Following analysis of the ellipsoidal sensor, a series of prismatic cap configurations were developed and analyzed using ZEMAX® optical design software. These various configurations are illustrated in FIGS. 26 and 27. In general, each of these concepts utilizes two internal transmission facets and three or five external facets inside the cap that help to totally internally reflect light along the inside of the prism portion of the cap. These sensor concepts can provide images of the critical angle between air and E48R (ZEONEX® E48R material with a refractive index of about 1.5305), air SPR lines, and tear SPR lines. It was. In one sensor concept, both critical angle and air SPR lines are captured in one image frame, and tear SPR lines are captured in subsequent image frames. In another sensor concept, all three lines are captured in a single image frame.
Example 6: Analysis of a self-calibrating sensor
[00264] FIG. 28 includes a set of layout sketches for sensors based on output from the ZEMAX® optical design software. Panel C in FIG. 28 shows two refracting facets (indicated by circled red numbers 1 and 7) placed on the inner surface of the sensor and uncovered light by total internal reflection. And a fifth surface (shown as surface 5 or sensing surface) partially covered with gold stripes that are SPR surfaces (shown as surfaces 2, 3, 5, and 6). An enlarged view of the sensor chip as shown in FIG. The gold coated portion of surface 5 provides the SPR line for both air and tear osmotic SPR measurements, and the uncoated portion of surface 5 provides the critical angle transition of air. Both the critical angle transition of air and the SPR line of air must be obtained before the surface 5 is wetted by tears.

  [00265] The upper left sketch of FIG. 28 shows the overall optical layout of the sensor and system. The four LEDs function as light sources, two can operate at a nominal 855 nm, and two can operate at a nominal 950 nm. Both sets of LEDs consist of 855 nm LEDs and 950 nm LEDs, each of which can be operated independently. A small dichroic beamsplitter so that the two beams from the first set of 855 nm and 950 nm LEDs propagate along the common beam path as indicated by the upper beam bundle starting from the first set of LEDs. (Not shown) to be combined into a single beam. Considering first the case where the 855 nm LED in the first set is activated, the beam shown as the top beam is directed through the window and cylindrical lens and then through the refractive facet 7 towards the facet 6. It is burned. At facet 6, the light beam is reflected towards facet 4, the sensor surface by total internal reflection. The design of the cylindrical lens is such that the light beam is nominally focused on a line on facet 4. The midpoint of the cone angle of light incident on the sensor surface is nominally 42 degrees, which allows acquisition of both the critical angle transition of air and the SPR minimum of air in a single image frame. At the sensor surface, the light beam depicted by the upper (light gray) beam bundle interacts with gold and the air in contact with the gold so as to form an air SPR line and a critical angle transition of air for a wavelength of 855 nm. Works.

  [00266] After the light beams interact at the sensing surface, the light gray light bundle light beam is totally internally reflected from facet 4 toward facet 2, and at facet 2 is reflected toward refractive facet 1 and refracted Go through facet 1 and hit the 2D CMOS imaging array. In the illustrated embodiment, the imaging array is a grayscale version of the APTINA® MT9P031 1 / 2.5 inch 5 Mp CMOS digital image sensor consisting of 2592 × 1944 active pixels. The imager converts incident light into a digital electronic signal consisting of digital data representing the intensity of light at each of the 2592 × 1944 active pixels in the imaging array. These data can then be processed using the differential signal processing techniques described above to find the exact location of the critical angle transition of air and the SPR minimum angle of air.

  [00267] When the critical angle transition of air and the minimum SPR angle of air are detected on the imaging array, the 855 nm LED is turned off, the 950 nm LED is activated, the critical angle transition of air at the 950 nm wavelength and the SPR of air A similar process continues to obtain a set of minimum angles. These data combinations comprise an automatic air calibration sequence that occurs each time the system is taken out of its “sleep” mode.

  [00268] In a similar manner, light from the second set of 855 nm and 950 nm LEDs is combined and propagated through the system along the path indicated by the bundle of dark gray rays shown in FIG. The The main difference between the first set of LEDs and the second set is that the light from the second set of LEDs is totally internally reflected by facet 5 on the way to the sensor facet and on the way to the imager It is totally internally reflected by facet 3. The effect of this difference is that the midpoint of the light cone from the second set of LEDs is incident on the sensor surface at a nominal angle of about 64.4 °. This nominal angle of incidence allows the generation of SPR data for liquids such as water and tears. As with the first set of LEDs, it is possible to obtain SPR data at 855 nm and 950 nm by simply alternating the operation of the 855 nm and 950 nm LEDs.

[00269] Panel A of FIG. 29 uses a single LED from the first set of LEDs, ZEMAX (SPR line of air and critical angle transition before surface 5 is wet with water (or tear). (Registered trademark) simulation. Panel B of FIG. 29 shows the SPR line obtained using one of the LEDs from the second set under the condition that the surface 5 is wet with water (or tears).
Example 7: Snell's law and critical angle transition
[00270] Acquisition of accurate and precise critical angle data is an important aspect of the calibration of the subject sensors and systems. FIG. 30 shows Snell's law (the law of refraction) and critical angle geometry. FIG. 30 shows the simple case of Snell's law and the critical angle for a single interface. More complex optical thin film analysis is critical regardless of the number of plane parallel layers between the incident medium and the exit medium, so long as the incident medium has a refractive index of n ₁ and the exit medium has a refractive index of n _2. It is shown that the angle is always given by θ _C = Sin−1 (n ₂ / n ₁ ). Thus, the critical angle is invariant to the material between the incident medium and the output medium and depends only on the values of n ₁ and n ₂ . As a result, the measurement of the critical angle position provides an important calibration factor for SPR measurements.

[00271] FIG. 31 shows the position of the critical angle for a gold layer on an incident medium having a refractive index of 1.51. The exit medium is air having a refractive index of 1.00027477. The gold thickness varies from zero thickness to 75 nm thickness. The critical angle remains stationary at 41.4757 ° throughout this gold thickness range, as shown in the reflectivity vs. incidence chart. Since air is only weakly dispersible with respect to wavelength and temperature (and its index is well characterized for both wavelength and temperature), the main contribution to the critical angle shift is the refraction of the incident medium. For the subject system, this is the refractive index of the sensor, and any mechanical mounting tolerances of the sensor to the optical chassis. As a result, the sensor mounting angle at the time of measurement, given critical angle measurements at 855 nm and 950 nm, and given the known and well-characterized wavelength and temperature dispersion of the ZEONEX® E48R sensor material It is possible to set two equations and two unknowns to characterize and the refractive index of E48R.
Example 8: Self-calibrating sensor concept 2
[00272] FIG. 32 shows the optical layout of sensor concept 2. This concept is much simpler than sensor concept 1 and includes a beam splitter (not shown), a single collimating lens, a single cylindrical lens that doubles as a window for the optical chassis, two internal facets and Utilizes two LEDs, one at 855 nm and the second at 950 nm, combined into a single beam using a sensor consisting of three external facets and an image detector. Light from an 855 nm LED or 950 nm LED follows essentially the same optical path. In operation, light from the active 855 nm LED is collimated by a collimating lens and then focused on a line on the sensor facet 3 by a cylindrical lens. After passing through the cylindrical lens, the beam is refracted by the facet 5 across the central axis of the sensor and reflected by the uncoated facet 2. The incident angle of the beam on facet 2 is about 42.0 ° so that a critical angle transition of air occurs on this surface. The reflected beam from facet 2 onto gold-coated sensor facet 3 at an incident angle of about 64.4 ° so as to produce an SPR minimum for water or tears near the central angle of the focused light cone. Incident. The gold thickness on facets 3 and 4 is about 45-50 nm. After reflection from the sensor surface 3, the beam is incident on the gold-coated facet 4 at an incident angle of about 42 ° so as to produce an SPR minimum of air upon reflection from the fourth facet. Finally, the beam exits the sensor by reflection through facet 1 and is rearranged parallel to the optical axis of the system by passing through a cylindrical lens and then the 2593 × 1944 pixel APTINA® described above. ) Incident on the imager.

  [00273] In a similar manner, SPR and critical angle data can be collected at a wavelength of 950 nm by turning off the 855 nm LED and turning on the 950 nm LED. The path taken by the 950 nm light is in this case virtually the same.

[00274] FIG. 33 shows the ZEMAX® of sensor concept 2 performance showing its critical angle transition, tear SPR line and air SPR line in a single image. A simulation is shown. In principle, sensor concept 2 has a complete set of air critical angle transition, tear SPR minimum, and air SPR minimum data in a single captured frame, as shown in FIG. Can be generated.
Example 9: Analysis of self-calibrating sensor concept 1
[00275] FIG. 34 shows a further development of sensor concept 1. FIG. FIG. 34 shows the physical size of both the LED and the imager as provided provided on a circuit board using a support chip according to XIMEA®. Compared to the optical layout in FIG. 28, the layout in FIG. 34 allows the top of the system to be placed so that the osmotic pressure measurement physician can more easily place the sensing surface of the sensor on the eye tear film. Note that it is flipped up and down for the purpose of providing a more direct line of sight beyond the sensor tip.

  [00276] Still referring to FIG. 34, light from LEDs emitted in the general direction of the sensor is collimated by a collimating lens, focused by a cylindrical lens, and enters an internal cavity portion of the sensor. Inside the sensor, the light focused by the cylindrical lens is reflected by the upper inner facet of the sensor and then internally reflected by three of the five outer facets of the sensor. The second facet of the three facets is a sensing surface that allows the light focused in a cylindrical manner to converge and interacts with the gold coating on the sensing surface and the medium in contact with the gold outer surface. Internal reflection by the surface following the sensor surface and subsequent refraction by the lower internal facet primarily serves to direct light exiting the sensor in the general direction of the image sensor. An optical wedge that may be omitted serves to direct the axis of the outgoing beam closer to the physical axis of the system so that its vertical profile is lower.

  [00277] FIG. 35 mounts sensors on a machined aluminum optical chassis that supports LEDs, optical components, and imagers in their proper locations for creating and imaging SPR lines and critical angle transitions. The structure for this is shown in more detail. 36 shows the length dimensions of the optical chassis, FIGS. 37 and 38 show the vertical dimensions of the chassis, and component callouts and more details regarding the mounting components that couple the sensor to the optical chassis. And provide.

  [00278] FIG. 39 shows the configuration of the optical chassis when surface mount LEDs are used. This layout also shows a cylindrical lens bonded to a plane parallel disk of optical glass that acts as a window to prevent contaminants from entering a series of optical components housed within the optical chassis. Adhering the cylindrical lens to the window helps to permanently set its alignment relative to other optical components in the chassis. FIG. 39 also shows the position of the polarizer and its barrel. The polarizer is used to form an SPR image and a critical angle transition image on the image sensor. Finally, the position of the beam splitter that combines the light from the various LEDs in the system is shown. FIG. 40 is a similar view of the chassis in a perspective view.

  [00279] FIG. 41 shows the optical and sensor chassis installed in its exterior housing, and also shows a control board used to detect switch closure and activate the LEDs in the optical chassis in the proper sequence. Indicates the position.

[00280] FIGS. 42-47 provide a more detailed view of the sensor. FIGS. 42 and 43 show three holding components that are spaced 120 ° apart and on which there are three small protrusions that serve to engage the first inner surface of the bayonet attachment mechanism of the optical chassis. These flexible portions and protrusions bias the sensor so that the three kinematic attachment points shown in FIG. 44 are in kinematic contact with the second inner surface of the bayonet attachment mechanism. FIG. 45 shows an outer end view of a sensor according to an embodiment of the present invention. In this figure, the holding component no longer has a slot found (using the mold flow analysis software application) that makes it difficult to completely fill the tab during the injection molding process. FIG. 46 shows an outer end view of the sensor in its mating bayonet mechanism of the optical chassis. FIG. 47 is a simulation of the appearance of the sensor that appears when molded with ZEONEX® E48R optical polymer. A sensing surface and a plurality of facets are identified.
Example 10: Benchtop sensor system
[00281] FIG. 48 is a diagram of a desktop or bench top system. As shown in FIG. 48, the bench top system comprises two LED collimators, in this example one operating at a nominal wavelength of 855 nm and the other operating at a nominal wavelength of 950 nm. An LED collimator consists of a point source LED followed by a circular sheet polarizer followed by a suitable collimating lens. The illustrated components are housed in a brass housing. Note that the wavelength of the collimator need not be 855 nm and 950 nm, but can be any pair of wavelengths suitable for the sensor and the test medium being analyzed.

  [00282] As shown in FIG. 48, light from the 855 nm LED collimator is incident on the reflective hypotenuse of the 90 ° prism and is reflected toward the beam splitter. In the beam splitter, a portion of the 855 nm beam passes through the beam splitter, then through the cylindrical lens to the SPR semi-cylindrical sensor, and finally the gold-coated microscope slide gold that was the index that matched the semi-cylinder. Focused on the coated external sensing surface. The angle of incidence of this 855 nm beam on the gold surface is within the critical angle range of 855 nm so that a critical angle transition of 855 nm air and SPR lines of air can be generated. In a similar manner, a portion of the beam from the 950 nm LED collimator can be reflected by a beam splitter, focused by a cylindrical lens, and enter a semi-cylinder to generate a critical angle transition of 950 nm air and air SPR lines. In addition, the gold-coated sensing surface can be impacted at an angle within a critical angle range of 950 nm.

  [00283] In a similar manner, the 855 nm beam reflected by the beam splitter and the 950 nm beam transmitted through the beam splitter are combined, reflected from the second reflective hypotenuse of the 90 ° prism, and passed through the second cylindrical lens. Then enter the semi-cylinder and impinge on the gold-coated microscope slide at an angle within the range of the SPR minimum, thus generating 855 nm and 950 nm SPR lines for liquids such as aqueous solutions, tears and the like.

  [00284] Light reflected from the gold-coated microscope slide passes through the semi-cylinder and exits the semi-cylinder in a general direction toward the image detector, generally using the signal processing techniques described above, the desktop Analyzed by computer or laptop computer.

  [00285] FIG. 49 is a perspective view of a bench top system without component labels, and FIG. 50 is a perspective view with components labeled. It should be noted that the optical chassis of the illustrated benchtop system is formed by computer numerical control (CNC) machining of its internal and external features from an aluminum solid billet. This provides a very stable and precise optical chassis, and all critical components that require precise alignment are attached to the chassis via a kinematic attachment mechanism. As a result, no adjustable optical mount or other similar adjustment is required to align the optics. FIG. 51 is a photograph of an integrated optical chassis and its integrated CNC machined cover.

  [00286] While the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, certain changes may be made without departing from the spirit or scope of the appended claims. And it will be readily apparent to those skilled in the art in light of the teachings of the present invention that modifications may be made.

  [00287] Thus, the foregoing merely illustrates the principles of the invention. It will be appreciated that those skilled in the art may devise various configurations that embody the principles of the invention and fall within the spirit and scope thereof, although not explicitly described or illustrated herein. Further, all examples and conditional languages listed herein are primarily intended to help readers understand the principles of the invention and the concepts that contribute to the advancement of the technology by the inventors. And should not be construed as limited to the examples and conditions specifically listed as such. Furthermore, all statements herein reciting principles and aspects of the invention and specific examples thereof are intended to encompass both structural and functional equivalents thereof. In addition, such equivalents include both currently known equivalents and equivalents developed in the future, ie, any developed element that performs the same function regardless of structure. The scope of the present invention is therefore not intended to be limited to the exemplary embodiments shown and described herein. Rather, the scope and spirit of the invention is embodied by the appended claims.

Claims (72)

A sensor comprising a sensing surface, the sensor comprising:
Directing a first optical signal to interact with the sensing surface at a first angle of incidence;
A sensor configured to direct a second optical signal to interact with the sensing surface at a second angle of incidence.   The sensor of claim 1, wherein the sensor comprises a plurality of facets.   The sensor according to claim 1, wherein the sensor has a truncated conical concave shape.   The sensor of claim 3, wherein the sensor comprises a plurality of facets on an inner surface and a plurality of facets on an outer surface.   The sensor of claim 4, wherein the sensor comprises two facets on the inner surface and four facets on the outer surface.   The sensor according to claim 1, wherein the sensing surface is disposed at a central portion of the sensor.   The sensor of claim 1, wherein the sensing surface comprises a covered area and an uncovered area.   The sensor according to claim 7, wherein the covered region comprises a translucent film comprising a noble metal.   The sensor according to claim 8, wherein the noble metal is gold, silver, aluminum, platinum, or palladium.   The sensor of claim 8, wherein the translucent film has a thickness in the range of about 0.5 nm to about 200 nm.   The sensor of claim 10, wherein the translucent film has a thickness of about 45 nm to about 50 nm.   The sensor according to claim 7, wherein the covered region comprises an adhesive layer disposed between the sensor and the translucent film.   The sensor of claim 12, wherein the adhesive layer has a thickness in the range of about 0.5 nm to about 200 nm.   The sensor of claim 12, wherein the adhesive layer has a thickness in the range of about 45 nm to about 50 nm.   The sensor of claim 12, wherein the adhesive layer comprises a material selected from chromium, titanium dioxide, titanium monoxide, silicon dioxide, and silicon monoxide.   The sensor according to claim 12, wherein the adhesive layer has a refractive index different from that of the sensor.   The sensor of claim 1, wherein the first angle of incidence ranges from about 40 degrees to about 70 degrees.   The sensor of claim 17, wherein the first angle of incidence ranges from about 40 degrees to about 45 degrees.   The sensor of claim 18, wherein the first angle of incidence is about 42 degrees.   The sensor of claim 1, wherein the second angle of incidence ranges from about 40 degrees to about 70 degrees.   21. The sensor of claim 20, wherein the second angle of incidence is in the range of about 62 degrees to about 67 degrees.   The sensor of claim 21, wherein the second angle of incidence is about 64 degrees.   The sensor of claim 1, wherein the sensor is adapted for sterilization. An optical chassis, the optical chassis comprising:
An optical signal generation component; and
A detection component; and
A processor;
A controller,
A computer-readable medium, the computer-readable medium comprising:
When executed by the processor, the controller
Directing an optical signal having a first wavelength to interact with the sensing surface at the first angle of incidence to generate a first critical angle signal;
Generating an image of the first critical angle signal using the detection component;
Determining a pixel position of a maximum value of the first critical angle signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the first angle of incidence to generate a second critical angle signal;
Generating an image of the second critical angle signal using the detection component;
Determining a pixel position of a maximum value of the second critical angle signal on the generated image;
24. The method according to any one of claims 1 to 23, comprising instructions for comparing the pixel positions of the maximum values of the first and second critical angle signals to determine a critical angle delta pixel value. Sensor.   25. The sensor of claim 24, wherein the sensing surface comprises a covered area and an uncovered area, and the first and second critical angle signals are generated from the uncovered area. An optical chassis, the optical chassis comprising:
An optical signal generation component; and
A detection component; and
A processor;
A controller,
A computer-readable medium, the computer-readable medium comprising:
When executed by the processor, the controller
Directing an optical signal having a first wavelength to interact with the sensing surface at the first angle of incidence to generate a first surface plasmon resonance (SPR) signal;
Generating an image of the first SPR signal using the detection component;
Determining a minimum pixel location of the first SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the first angle of incidence to generate a second surface plasmon resonance (SPR) signal;
Generating an image of the second SPR signal using the detection component;
Determining a minimum pixel position of the second SPR signal on the generated image;
24. The method of any one of claims 1 to 23, comprising instructions for comparing the pixel positions of the minimum values of the first and second SPR signals to determine a first SPR delta pixel value. The sensor described. When the computer readable medium is executed by the processor, the controller
Directing an optical signal having a first wavelength to interact with the sensing surface at the second angle of incidence to generate a third surface plasmon resonance (SPR) signal;
Generating an image of the third SPR signal using the detection component;
Determining a minimum pixel location of the third SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the second angle of incidence to generate a fourth SPR signal;
Generating an image of the fourth surface plasmon resonance (SPR) signal using the detection component;
Determining a minimum pixel position of the fourth SPR signal on the generated image;
27. The sensor of claim 26, further comprising instructions for comparing the pixel locations of the minimum values of the third and fourth SPR signals to determine a second SPR delta pixel value.   28. A sensor according to claim 26 or 27, wherein the sensing surface comprises a covered area and an uncovered area, and the SPR signal is generated from the covered area. When the computer readable medium is executed by the processor, the controller
Directing an optical signal having a first wavelength to interact with a coverage region of the sensing surface at the first angle of incidence to generate a first surface plasmon resonance (SPR) signal;
Generating an image of the first SPR signal using the detection component;
Determining a minimum pixel location of the first SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the first angle of incidence to generate a second surface plasmon resonance (SPR) signal;
Generating an image of the second SPR signal using the detection component;
Determining a minimum pixel position of the second SPR signal on the generated image;
25. The sensor of claim 24, further comprising instructions for comparing the pixel positions of the minimum values of the first and second SPR signals to determine a first SPR delta pixel value. When the computer readable medium is executed by the processor, the controller
Directing an optical signal having a first wavelength to interact with the sensing surface at the second angle of incidence to generate a third SPR signal;
Generating an image of the third SPR signal using the detection component;
Determining a minimum pixel location of the third SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the second angle of incidence to generate a fourth SPR signal;
Generating an image of the fourth SPR signal using the detection component;
Determining a minimum pixel position of the fourth SPR signal on the generated image;
30. The sensor of claim 29, further comprising instructions for comparing the pixel locations of the minimum values of the third and fourth SPR signals to determine a second SPR delta pixel value.   31. A sensor according to any one of claims 24 to 30, wherein the optical signal generating component comprises a laser or a light emitting diode (LED).   32. A sensor according to claim 31, wherein the laser or LED emits visible or infrared light.   35. The sensor of claim 32, wherein the laser or LED emits light having a wavelength in the range of about 400 nm to about 1000 nm.   34. The sensor of claim 33, wherein the laser or LED is configured to emit light having a wavelength of about 855 nm.   34. The sensor of claim 33, wherein the laser or LED is configured to emit light having a wavelength of about 950 nm.   36. A sensor according to any one of claims 24 to 35, wherein the optical chassis further comprises one or more optical signal manipulation components.   37. A sensor according to any one of claims 24 to 36, wherein the detection component comprises an image sensor.   38. The sensor of claim 37, wherein the image sensor is a charge coupled device (CCD) camera or a scientific complementary metal oxide semiconductor (sCMOS) camera.   38. The sensor of claim 37, wherein the image sensor is an active pixel sensor (APS).   40. The sensor of any one of claims 24 to 39, further comprising a plurality of retention fixtures configured to removably couple the sensor to the optical chassis.   40. The sensor of any one of claims 24 to 39, further comprising an alignment component configured to align the sensor with the optical chassis.   42. The sensor of claim 41, wherein the alignment component comprises a tapered centering component.   40. A sensor according to any one of claims 24 to 39, further comprising a plurality of kinematic attachment components. (I) a sensor comprising a sensing surface comprising an uncovered region, wherein the sensor is
Directing a first optical signal to interact with the sensing surface at a first angle of incidence;
Configured to direct a second optical signal to interact with the sensing surface at a second angle of incidence;
(Ii)
An optical chassis,
An optical signal generation component; and
A detection component; and
A processor;
A controller,
An optical chassis comprising a computer readable medium,
When the computer-readable medium is executed by the processor, the computer
Directing an optical signal having a first wavelength to interact with the sensing surface at the first angle of incidence to generate a first critical angle signal;
Generating an image of the first critical angle signal using the detection component;
Determining a pixel position of the first critical angle signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the first angle of incidence to generate a second critical angle signal;
Generating an image of the second critical angle signal using the detection component;
Determining a pixel location of the second critical angle signal on the generated image;
Instructions for comparing the pixel positions of the first and second critical angle signals to determine a critical angle delta pixel value;
system.   45. The system of claim 44, wherein the sensing surface comprises a covered area and an uncovered area, and the first and second critical angle signals are generated from the uncovered area. (I) a sensor comprising a sensing surface comprising a covered region, wherein the sensor is
Directing a first optical signal to interact with the sensing surface at a first angle of incidence;
Configured to direct a second optical signal to interact with the sensing surface at a second angle of incidence;
(Ii)
An optical chassis,
An optical signal generation component; and
A detection component; and
A processor;
A controller,
An optical chassis comprising a computer readable medium,
When the computer-readable medium is executed by the processor, the computer
Directing an optical signal having a first wavelength to interact with the sensing surface at the first angle of incidence to generate a first surface plasmon resonance (SPR) signal;
Generating an image of the first SPR signal using the detection component;
Determining a minimum pixel location of the first SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the first angle of incidence to generate a second surface plasmon resonance (SPR) signal;
Generating an image of the second SPR signal using the detection component;
Determining a minimum pixel position of the second SPR signal on the generated image;
Comprising instructions for comparing the pixel positions of the minimum values of the first and second SPR signals to determine an SPR delta pixel value;
system. When the computer readable medium is executed by the processor, the controller
Directing an optical signal having a first wavelength to interact with the sensing surface at the second angle of incidence to generate a third surface plasmon resonance (SPR) signal;
Generating an image of the third SPR signal using the detection component;
Determining a minimum pixel location of the third SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the second angle of incidence to generate a fourth surface plasmon resonance (SPR) signal;
Generating an image of the fourth SPR signal using the detection component;
Determining a minimum pixel position of the fourth SPR signal on the generated image;
47. The system of claim 46, further comprising instructions for comparing the pixel positions of the minimum values of the third and fourth SPR signals to determine a second SPR delta pixel value.   48. The system of claim 46 or 47, wherein the sensing surface comprises a covered area and an uncovered area, and the SPR signal is generated from the covered area. When the computer readable medium is executed by the processor, the controller
Directing an optical signal having a first wavelength to interact with the coated region of the sensing surface at the first angle of incidence to generate a first surface plasmon resonance (SPR) signal;
Generating an image of the first SPR signal using the detection component;
Determining a minimum pixel location of the first SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the first angle of incidence to generate a second surface plasmon resonance (SPR) signal;
Generating an image of the second SPR signal using the detection component;
Determining a minimum pixel position of the second SPR signal on the generated image;
46. The method of claim 45, further comprising instructions for comparing the pixel locations of the minimum values of the first and second SPR signals on the generated image to determine a first SPR delta pixel value. system. When the computer readable medium is executed by the processor, the controller
Directing an optical signal having a first wavelength to interact with the sensing surface at the second angle of incidence to generate a third SPR signal;
Generating an image of the third SPR signal using the detection component;
Determining a minimum pixel location of the third SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the second angle of incidence to generate a fourth SPR signal;
Generating an image of the fourth SPR signal using the detection component;
Determining a minimum pixel position of the fourth SPR signal on the generated image;
50. The system of claim 49, further comprising instructions for comparing the pixel locations of the minimum values of the third and fourth SPR signals to determine a second SPR delta pixel value.   51. A system according to any one of claims 44 to 50, wherein the sensor is configured to be removably coupled to the optical chassis.   52. A system according to any one of claims 44 to 51, wherein the system is a bench top system.   52. A system according to any one of claims 44 to 51, wherein the system is a handheld system. A method for determining the osmotic pressure of a sample, said method comprising:
Contacting the sensing surface of the system of any one of claims 46 to 53 with a reference medium;
Directing an optical signal having a first wavelength to interact with the sensing surface at the first angle of incidence to generate a first reference surface plasmon resonance (SPR) signal;
Generating an image of a first reference SPR signal using the detection component;
Determining a minimum pixel location of the first reference SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the first angle of incidence to generate a second reference SPR signal;
Generating an image of the second reference SPR signal using the detection component;
Determining a minimum pixel location of the second reference SPR signal on the generated image;
Comparing the pixel position of the minimum value of the first and second reference SPR signals to determine a reference medium SPR delta pixel value;
Contacting the sensing surface with the sample;
Directing an optical signal having a first wavelength to interact with the sensing surface at the second angle of incidence to generate a first test SPR signal;
Generating an image of the first test SPR signal using the detection component;
Determining a minimum pixel location of the first test SPR signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the second angle of incidence to generate a second test SPR signal;
Determining a minimum pixel location of the second test SPR signal on the generated image;
Comparing the pixel locations of the minimum values of the first and second test SPR signals to determine a test media SPR delta pixel value;
Comparing the reference media SPR delta pixel value with the test media SPR delta pixel value to generate a first corrected delta pixel value;
Comparing the first corrected delta pixel value with a calibration data set to determine the osmotic pressure of the sample. Contacting the sensing surface with the reference medium;
Directing an optical signal having a first wavelength to interact with the sensing surface at the first angle of incidence to generate a first critical angle signal;
Generating an image of the first critical angle signal using the detection component;
Determining a pixel position of a maximum value of the first critical angle signal on the generated image;
Directing an optical signal having a second wavelength to interact with the sensing surface at the first angle of incidence to generate a second critical angle signal;
Generating an image of the second critical angle signal using the detection component;
Determining a pixel position of a maximum value of the second critical angle signal on the generated image;
Comparing the pixel position of the maximum value of the first and second critical angle signals to determine a critical angle delta pixel value;
Comparing the first corrected delta pixel value with the critical angle delta pixel value to determine a second corrected delta pixel value;
55. The method of claim 54, further comprising comparing the second corrected delta pixel value to a calibration data set to determine the osmotic pressure of the sample.   56. The method of claim 55, wherein the images of the first and second reference SPR signals and the first and second critical angle signals are captured in a single image frame. Comparing the first or second corrected delta pixel value with an external environment parameter to generate an external environment corrected delta pixel value;
57. The method of any one of claims 54 to 56, further comprising comparing the external environment correction delta pixel value to a calibration data set to determine the osmotic pressure of the sample.   58. The method of claim 57, wherein the external environmental parameter is selected from the group comprising temperature, pressure, and humidity. A method for verifying a quality parameter of a sensor, the method comprising:
Contacting the sensing surface of the system of any one of claims 46 to 53 with a reference medium;
Directing an optical signal having a first wavelength to interact with the sensing surface at the first angle of incidence to generate a first reference surface plasmon resonance (SPR) signal;
Generating an image of a first reference SPR signal using the detection component;
Determining one or more characteristics of the first reference SPR signal;
Comparing the one or more characteristics of the first reference SPR signal with a calibration data set to verify the quality parameter of the sensor.   The quality parameters of the sensor are the thickness of the translucent film disposed on the sensing surface, the thickness of the adhesive layer disposed on the sensing surface, and the thickness of the translucent film disposed on the sensing surface. 60. The method of claim 59, selected from the group comprising material purity and material purity in an adhesive layer disposed on the sensing surface.   60. The method of claim 59, wherein the characteristic of the first reference SPR signal is selected from a group comprising a contrast value, shape, or dimension of the first reference SPR signal. A method for verifying a quality parameter of a sensor, said method comprising:
Contacting the sensing surface of the system of any one of claims 44, 45, or 49 to 53 with a reference medium;
Directing an optical signal having a first wavelength to interact with the sensing surface at the first angle of incidence to generate a first reference critical angle signal;
Generating an image of the first reference critical angle signal using the detection component;
Determining one or more characteristics of the first reference critical angle signal;
Comparing the one or more characteristics of the first reference critical angle signal with a calibration data set to verify the quality parameter of the sensor.   The quality parameters of the sensor are the thickness of the translucent film disposed on the sensing surface, the thickness of the adhesive layer disposed on the sensing surface, and the thickness of the translucent film disposed on the sensing surface. 63. The method of claim 62, selected from the group comprising material purity and material purity in an adhesive layer disposed on the sensing surface.   64. The method of claim 62, wherein a characteristic of the first reference critical angle signal is selected from the group comprising a contrast value, shape, or dimension of the first reference critical angle signal.   65. A method according to any one of claims 54 to 64, wherein the optical signal having the first wavelength and the optical signal having a second wavelength are directed to interact with the sensing surface at the same time.   65. A method according to any one of claims 54 to 64, wherein the optical signal having the first wavelength and the optical signal having the second wavelength are directed to interact with the sensing surface in a gated fashion. .   67. A method according to any one of claims 54 to 66, wherein the calibration data set is stored in a read only memory of a processor of the system.   68. A method according to any one of claims 54 to 67, wherein the reference medium is air and the sample is tear fluid.   69. The method of claim 68, wherein the tear remains in contact with the subject's eye while the method is being performed.   70. The method of any one of claims 54 to 69, wherein the first angle of incidence is in the range of about 40 degrees to about 45 degrees and the second angle of incidence is in the range of about 62 degrees to about 67 degrees. the method of.   71. The method of claim 70, wherein the first angle of incidence is about 42 degrees and the second angle of incidence is about 64 degrees.   72. The method of any one of claims 54 to 71, wherein the first wavelength is about 855 nm and the second wavelength is about 950 nm.